UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.    )

Filed by the Registrantx   Filed by a Party other than the Registrant¨

Check the appropriate box:

AMEREN CORPORATION

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

NOTICE OF ANNUAL MEETING OF

SHAREHOLDERS AND PROXY STATEMENT OF

AMEREN CORPORATION

IMPORTANT

If you plan to attend the annual meeting of shareholders, please advise the Company in your proxy vote (by telephone or the Internet or by checking the appropriate box on the proxy card) and bring the Admission Ticket on the bottom of your proxy card. Persons without tickets will be admitted to the meeting upon verification of their shareholdings in the Company. If your shares are held in the name of your broker, bank or other nominee, you must bring an account statement or letter from the nominee indicating that you were the beneficial owner of the shares on March 4, 2005,6, 2006, the record date for voting. Please note that cameras and other recording devices will not be allowed in the meeting.

Please vote by proxy (via telephone or the Internet or the enclosed proxy card) even if you own only a few shares. If you attend the meeting and want to change your proxy vote, you can do so by voting in person at the meeting.

AMEREN CORPORATION

NOTICE OF ANNUAL MEETING OF SHAREHOLDERS

To the Shareholders of

    AMEREN CORPORATION

We will hold the Annual Meeting of Shareholders of Ameren Corporation at The Saint Louis Art Museum, Forest Park, One Fine Arts Drive, St. Louis, Missouri, on Tuesday, April 26, 2005,May 2, 2006, at 9:00 A.M., for the purposes of

The Board of Directors of the Company presently knows of no other business to come before the meeting.

If you owned shares of the Company’s Common Stock at the close of business on March 4, 2005,6, 2006, you are entitled to vote at the meeting and at any adjournment thereof. All shareholders are requested to be present at the meeting in person or by proxy so that a quorum may be assured.

You may vote via telephone or the Internet or, if you prefer, you may sign and return the enclosed proxy card in the enclosed envelope. Your prompt vote by proxy will reduce expenses. Instructions for voting by telephone or the Internet are included with this mailing. If you attend the meeting, you may revoke your proxy by voting in person.

By order of the Board of Directors.

STEVEN R. SULLIVAN

Secretary

St. Louis, Missouri

March 15, 20052006

TABLE OF CONTENTS

i

PROXY STATEMENT OF AMEREN CORPORATION

(First sent or given to shareholders on or about March 15, 2005)2006)

Principal Executive Offices:

One Ameren Plaza

1901 Chouteau Avenue, St. Louis, MO 63103

INFORMATION ABOUT THE ANNUAL SHAREHOLDERS MEETING

This solicitation of proxies is made by the Board of Directors of Ameren Corporation (the “Company” or “Ameren”) for the Annual Meeting of Shareholders of the Company to be held on Tuesday, April 26, 2005May 2, 2006 (the “Annual Meeting”), and at any adjournment thereof. The Annual Meeting will be held at The Saint Louis Art Museum, Forest Park, One Fine Arts Drive, St. Louis, Missouri, at 9:00 A.M. Central Time.

The Company is a holding company, the principal first tier subsidiaries of which are Union Electric Company, doing business as AmerenUE (“UE”), Central Illinois Public Service Company, doing business as AmerenCIPS (“CIPS”), CILCORP Inc. (“CILCORP”), Illinois Power Company, doing business as AmerenIP (“IP”), Ameren Services Company (“Ameren Services”), Ameren Energy Resources Company (“AER”) and Ameren Energy, Inc. (“AE”). CILCORP is the parent company of Central Illinois Light Company, doing business as AmerenCILCO (“CILCO”). AER is the parent company of Ameren Energy Generating Company (“AEG”). On September 30, 2004, the Company concluded its acquisition from Dynegy Inc. and its subsidiaries of all of the common stock of IP. The Company holds either directly or indirectly more than 50% of the voting power of UE, CIPS, CILCORP, IP, Ameren Services, AER, AE, AEG and CILCO. As a result, each of these subsidiaries constitutes a “controlled company” as defined by the New York Stock Exchange (“NYSE”) listing standards.

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VOTING

Who Can Vote

The accompanying proxy card represents all shares registered in the name(s) shown thereon, including shares in the Company’s dividend reinvestment and stock purchase plan (DRPlus Plan). Participants in the Savings Investment Plans of Ameren and its subsidiaries (401(k) Plans) and the Ameren Corporation Long-Term Incentive Plan of 1998 will receive separate proxies for shares in such plans.

Only shareholders of the Company’s Common Stock of record at the close of business on the Record Date, March 4, 2005,6, 2006, are entitled to vote at the Annual Meeting. In order to conduct the Annual Meeting, holders of more than one-half of the outstanding shares entitled to vote must be present in person or represented by proxy so that there is a quorum. A quorum consists of a majority of the outstanding shares entitled to vote, present or represented by proxy. The voting securities of the Company on March 4, 2005,6, 2006, consisted of 195,403,131204,881,293 shares of Common Stock. Each share of Common Stock is entitled to one vote. It is important that you vote promptly so that your shares are counted toward the quorum.

In determining whether a quorum is present at the Annual Meeting, shares registeredrepresented by a proxy which directs that the shares abstain from voting or that a vote be withheld on a matter, shall be deemed to be represented at the meeting for quorum purposes. Shares as to which voting instructions are given as to at least one of the matters to be voted on shall also be deemed to be so represented. If the proxy states how shares will be voted in the nameabsence of instructions by the shareholder, such shares shall be deemed to be represented at the meeting.

In all matters, including the election of directors, every decision of a brokermajority of the shares entitled to vote on the subject matter and represented in person or other nominee,by proxy at the meeting at which are voted on any matter, willa quorum

is present shall be included.valid as an act of the shareholders. In tabulating the number of votes cast,on such matters (i) shares represented by a proxy which directs that the shares abstain from voting or that a vote be withheld votes, abstentions and non-voteson a matter shall be deemed to be represented at the meeting as to such matter, (ii) except as provided in (iii) below, shares represented by banks and brokersa proxy as to which voting instructions are not included.given as to one or more matters to be voted on shall not be deemed to be represented at the meeting for the purpose of the vote as to such matter or matters, and (iii) a proxy which states how shares will be voted in the absence of instructions by the shareholder as to any matter shall be deemed to give voting instructions as to such matter. Shareholder votes are tabulatedcertified by independent inspectors of election.

The Board of Directors has adopted a confidential voting policy for proxies. This policy does not prohibit disclosure where it is required by applicable law.

How You Can Vote

By Proxy.    Before the Annual Meeting, you can give a proxy to vote your shares of the Company’s Common Stock in one of the following ways:

The telephone and Internet voting procedures are designed to confirm your identity and to allow you to give your voting instructions. If you wish to vote by telephone or the Internet, please follow the instructions on your proxy card. Additional instructions will be provided on the telephone message and website. Please have your proxy card at hand when voting.

If you mail us your properly completed and signed proxy card, or vote by telephone or the Internet, your shares of the Company’s Common Stock will be voted according to the choices that you specify. If you sign and mail your proxy card without marking any choices, your proxy will be voted as recommended by the Board – FOR the Board’s nominees for director Item (1), FOR approving the 2006 Omnibus Incentive Compensation Plan Item (2), FOR ratifying the appointment of the independent auditors Item (2)(3), AGAINST the shareholder proposal Item (3)(4), and AGAINSTin the shareholder proposal Item (4). On any other matters,discretion of the named proxies will use their discretion.upon such other matters as may properly come before the meeting.

If you hold any shares in the Savings Investment Plans of Ameren and its subsidiaries, your completed proxy card or telephone or Internet proxy vote will serve as voting instructions to the plan trustee. However, your voting instructions must be received at least five days prior to the Annual Meeting in order to count. In accordance with the terms of the plans, the trustee will vote all of the shares held in the plans in the same proportion as the actual proxy votes submitted by plan participants.

If you have shares registered in the name of a bank, broker, or other registered owner or nominee, you should receive instructions from that registered owner about how to instruct them to vote those shares.

In Person.    You may come to the Annual Meeting and cast your vote there. Only shareholders of record at the close of business on the Record Date, March 4, 2005,6, 2006, are entitled to vote at the Annual Meeting.

How You Can Revoke Your Proxy

You may revoke your proxy at any time after you give it and before it is voted by entering a new vote by telephone or the Internet or by delivering either a written revocation or a signed proxy bearing a later date to the Secretary of the Company or by voting in person at the Annual Meeting. To revoke a proxy by telephone or the Internet, you must do so by 11:59 P.M. Central Time on April 24, 200530, 2006 (following the directions on the proxy card). Attendance at the Annual Meeting will not cause your previously granted proxy to be revoked unless you specifically so request.

OTHER ANNUAL MEETING MATTERS

How You Can Obtain Materials For the Annual Meeting

This proxy statement and the accompanying proxy card are first being mailed to shareholders on or about March 15, 2005.2006. In the same package with this proxy material, you should have received a copy of the Company’s 20042005 Summary Annual Report to Shareholders and its Annual Report to the Securities and Exchange Commission (the “SEC”) on Form 10-K for the year ended December 31, 20042005 (the “2004“2005 Form 10-K”), including consolidated financial statements. When you receive this package, if all of these materials are not included, please contact us and a copy of any missing material will be sent at no expense to you.

You may reach us:

Office of the Secretary

Ameren Corporation

P.O. Box 66149, MCMail Code 1370

St. Louis, MO 63166-6149

How You Can Review the List of Shareholders

The names of shareholders of record entitled to vote at the Annual Meeting will be available at the Annual Meeting and, for 10 days prior to the Annual Meeting, at the Office of the Secretary of the Company.

Webcast of the Annual Meeting

The Annual Meeting will also be webcast on April 26, 2005.May 2, 2006. You are invited to visithttp://www.ameren.com at 9:00 A.M. on April 26, 2005,May 2, 2006, to hear the webcast of the Annual Meeting. On the home page, you will click on “Live Webcast Annual Meeting April 26, 2005,May 2, 2006, 9:00 A.M. CT,” then the appropriate audio link. The webcast will remain on the Company’s website for one year. You cannot record your vote on this webcast.

ITEMS YOU MAY VOTE ON

Item (1):    Election of Directors

TwelveEleven directors are to be elected at the Annual Meeting to serve until the next annual meeting of shareholders and until their respective successors have been duly elected and qualified. In the absence of instructions to the contrary, executed proxies will be voted in favor of the election of the persons listed below. In the event that any nominee for election as director should become unavailable to serve, votes will be cast, pursuant to the enclosed proxy card, for such substitute nominee or nominees as may be nominated by the Nominating and Corporate Governance Committee of the Board of Directors and approved by the Board of Directors. The Company’s Board of Directors is currently comprised of 11 members. A vacancy on the Board was created by the death of Paul L. Miller, Jr. in July 2005. The Board of Directors has decided not to fill the vacancy created by Mr. Miller’s death at this time. The Board of Directors knows of no reason why any nominee will not be able to serve as director. The 1211 nominees for director who receive the most votesvote of at least a majority of the shares entitled to vote in the election of directors and represented in person or by proxy at the meeting at which a quorum is present will be elected. Shareholders may not cumulate votes in the election of directors.

The Company’s Board of Directors is currently comprised of 14 members. Consistent with In the Company’s By-Laws,event any nominee for re-election fails to obtain the Board’s membership was increased from 12 withrequired majority vote, such nominee will tender his or her resignation as a director for consideration by the Board’s election of

Mr. Patrick T. Stokes effective in December 2004Nominating and of Dr. Gayle P. W. Jackson effective in February 2005. Mr. James C. Johnson has been nominated for election to the Board for the first time at the Annual Meeting. Messrs. Clifford L. Greenwalt, Thomas A. Hays and John Peters MacCarthy, who have been members of the Board since 1997, are completing their director service at the Annual Meeting pursuant to the Company’s age policy for directors. As a result of these retirements, the sizeCorporate Governance Committee of the Board of DirectorsDirectors. The Nominating and Corporate Governance Committee will be reduced to 12 members effective asevaluate the best interests of the Annual Meeting.Company and its shareholders and will recommend to the Board the action to be taken with respect to any such tendered resignation.

Information Concerning Nominees to the Board of Directors

The nominees for the Board of Directors of the Company are listed below, along with their age as of December 31, 2004,2005, tenure as director and business background for at least the last five years. Each nominee has consented to being nominated for director and has agreed to serve if elected. No arrangement or understanding exists between any nominee and the Company or, to the Company’s knowledge, any other person or persons pursuant to which any nominee was or is to be selected as a director or nominee. Except for Mr. Johnson, allAll of the nominees are currently directors of the Company. Each of the current directors hasCompany and have been previously elected by the Company’s shareholders at prior annual meetings, except for Mr. Stokes and Dr. Jackson who were initially elected by the directors to fill vacancies on the Board in December 2004 and February 2005, respectively. Mr. Stokes, Dr. Jackson and Mr. Johnson, all of whom are non-management director nominees, were initially recommended for membership on the Board by current non-management directors.meetings. There are no family relationships between any director, executive officer, or person nominated or chosen by the Company to become a director or executive officer except that Mr. Charles W. Mueller is the father of Michael G. Mueller, who is an executive officer of certain Company subsidiaries. See “Corporate Governance – Certain Relationships and Related Transactions” below for further information on this family relationship and certain other reportable family relationships with employees of the Company who are not executive officers. All of the nominees for election to the Board were unanimously recommended by the Nominating and Corporate Governance Committee of the Board of Directors and were unanimously nominated by the Board of Directors.

		SUSAN S. ELLIOTT Chairman and Co-Chief Executive Officer of Systems Service Enterprises, Inc., a privately held information technology firm. Ms. Elliott founded Systems Service Enterprises, Inc. in 1966. Director of the Company since 2003. Ms. Elliott is a past Chairman of the Federal Reserve Bank of St. Louis. Other directorships: Angelica Corporation. Age: 68.

Chairman and Co-Chief Executive Officer of Systems Service Enterprises, Inc., a privately held information technology firm. Ms. Elliott founded Systems Service Enterprises, Inc. in 1966. Director of the Company since 2003. Ms. Elliott is a past Chairman of the Federal Reserve Bank of St. Louis. Other directorships: Angelica Corporation. Age: 67.

		GAYLE P. W. JACKSON, Ph.D. President of Energy Global, Inc., a consulting firm which specializes in corporate development, diversification and government relations strategies for energy companies. From 2002 to 2004, Dr. Jackson served as Managing Director of FE Clean Energy Group, a global private equity management firm that invests in energy companies and projects in Central and Eastern Europe, Latin America and Asia. From 1985 to 2001, Dr. Jackson was President of a consulting firm that advised energy companies on corporate development and diversification strategies and national and international governmental institutions on energy policy. From 1985 to 1995, she was Chief of Staff of the Coal Industry Advisory Board, which was established by the Paris-based International Energy Agency to obtain expert advice from industry executives on strategies for reducing dependence on oil. From 1978 to 1985, she held corporate planning, business development and international sales and marketing positions at Peabody Holding Company, Inc. Dr. Jackson is Deputy Chairman of the Federal Reserve Bank of St. Louis. Director of the Company since February 2005. Age: 58. JAMES C. JOHNSON Vice President, Corporate Secretary and Assistant General Counsel of The Boeing Company,an aerospace and defense firm. Mr. Johnson joined The Boeing Company in May 1998 and has served in his current position since December 2003. Prior to joining The Boeing Company, Mr. Johnson served as Vice President, Secretary and Assistant General Counsel of Northrop Grumman Corporation from 1988 to 1998 Age: 52. RICHARD A. LIDDY Retired Chairman of GenAmerica Financial Corporation, which provides life, pension, annuity and related insurance products and services. Mr. Liddy served as Chairman of the Board of GenAmerica Financial from September 2000 to April 2002. He also served as Chairman of the Board of Reinsurance Group of America from May 1993 to April 2002. Mr. Liddy was President of GenAmerica Financial from May 1988 to September 2000 and Chief Executive Officer of General American Life Insurance Company from May 1992 to September 2000. In January 2000, while Mr. Liddy served as President of GenAmerica Financial Corporation, GenAmerica sold its mutual holding company to Metropolitan Life Insurance Company. At the request of the Missouri State Insurance Department, a receiver was appointed in order to oversee the equitable distribution of proceeds to policyholders. Director of the Company since 1997. Director of CILCORP and, until April 2004, director of the other following Ameren “controlled companies”: CILCO; UE; CIPS; AEG. Other directorships: Brown Shoe Company, Inc.; Ralcorp Holdings Inc.; Energizer Holdings, Inc. Age: 69. GORDON R. LOHMAN Retired Chairman and Chief Executive Officer of AMSTED Industries Incorporated, Chicago, Illinois, a manufacturer of railroad, construction, and general industrial products. Mr. Lohman was elected President of AMSTED Industries in 1988 and became Chief Executive Officer in 1990 and Chairman in 1997. He retired in 1999. Director of the Company since 1997. Other directorships: Fortune Brands, Inc. Age: 70. RICHARD A. LUMPKIN Chairman of Consolidated Communications, Inc., a telecommunications holding company. Mr. Lumpkin assumed his present position as Chairman of Consolidated Communications, Inc. on January 1, 2003 upon the acquisition of the former Illinois Consolidated Telephone Company from McLeodUSA Incorporated. Prior to the acquisition, Mr. Lumpkin had served as President of Illinois Consolidated Telephone Company since 1977 and also Chairman and Chief Executive Officer since 1990. As a result of a September 1997 merger, he also had served as Vice Chairman of McLeodUSA Incorporated until April 2002. In order to complete a recapitalization, McLeodUSA Incorporated filed, in January 2002, a pre-negotiated plan of reorganization through a Chapter 11 bankruptcy petition filed in the United States Bankruptcy Court for the District of Delaware. In April 2002, McLeodUSA Incorporated’s plan of reorganization became effective and it emerged from Chapter 11 protection. Director of the Company since 1997. Director of the following Ameren “controlled companies” until April 2004: CILCORP; CILCO; UE; CIPS; AEG. Other directorships: Consolidated Communications, Inc.; First Mid-Illinois Bancshares, Inc.; First Mid-Illinois Bank & Trust. Age: 69. PAUL L. MILLER, JR. President and Chief Executive Officer of P. L. Miller & Associates, a management consulting firm which specializes in strategic and financial planning for privately held companies and distressed businesses and in international business development. He is also a principal in Stewart, Miller and Associates, a financial advisory firm for small to middle market companies. Mr. Miller has served as President of an international subsidiary of an investment banking firm, and for over 20 years was President of consumer product manufacturing and distribution firms. Director of the Company since 1997. Director of the following Ameren “controlled companies” until April 2004: CILCORP; CILCO; UE; CIPS; AEG. Other directorships: LMI Aerospace, Inc.; Kennedy Capital Management, Inc.; Piedmont Investment Advisors, LLC. Age: 62. CHARLES W. MUELLER Retired Chairman and Chief Executive Officer of the Company, UE and Ameren Services and retired Chairman of CILCORP and CILCO. Mr. Mueller began his career with UE in 1961 as an engineer and held various positions with UE and other Ameren subsidiaries during his employment. He was elected President of UE in 1993 and Chief Executive Officer in 1994. Mr. Mueller was elected Chairman, Chief Executive Officer and President of Ameren upon its formation in 1997. He relinquished his position as President of Ameren, UE and Ameren Services in 2001. He was elected Chairman of CILCORP and CILCO in January 2003. Mr. Mueller retired as an officer of Ameren and its subsidiaries on December 31, 2003. Director of the Company since 1997. Mr. Mueller is a past Chairman and former director of the Federal Reserve Bank of St. Louis. Other directorships: Angelica Corporation. Age: 66. DOUGLAS R. OBERHELMAN Group President of Caterpillar Inc., a maker of construction and mining equipment, diesel and natural gas engines and industrial gas turbines. Mr. Oberhelman joined Caterpillar in 1975. He held a variety of positions, including senior finance representative based in South America for Caterpillar Americas Co. and region finance manager and district manager for Caterpillar’s North American Commercial Division, before his appointment as managing director and vice general manager of strategic planning at Shin Caterpillar Mitsubishi Ltd. (Toyko) in 1991. He was elected a Vice President in 1995 when he served as Caterpillar’s Chief Financial Officer. In 1998, he accepted leadership of Caterpillar’s Engine Products Division. Mr. Oberhelman was elected a Group President in 2001 with responsibility for Caterpillar’s corporate financial, audit and compliance, and legal divisions. Director of the Company since 2003. Director of the following Ameren “controlled companies” until April 2004: CILCORP; CILCO; UE; CIPS; AEG. Other directorships: South Side Bank (in Peoria, Illinois). Age: 51. GARY L. RAINWATER Chairman, Chief Executive Officer and President of the Company, UE, CILCORP and Ameren Services and Chairman and Chief Executive Officer of CIPS, CILCO and IP. Mr. Rainwater began his career with UE in 1979 as an engineer and has held various positions with UE and other Ameren subsidiaries during his employment. He was elected President and Chief Operating Officer of the Company, UE and Ameren Services in 2001. Effective January 1, 2004, Mr. Rainwater was elected to serve as Chairman and Chief Executive Officer of the Company, UE and Ameren Services in addition to his position as President. At that time, he was also elected Chairman of CILCORP and CILCO in addition to his position as Chief Executive Officer and President of those companies which he assumed in 2003. In September 2004, upon Ameren’s acquisition of IP, Mr. Rainwater was elected Chairman, Chief Executive Officer and President of IP. He currently holds the position of Chairman and Chief Executive Officer of CIPS, CILCO and IP after relinquishing his position as President in October 2004. Director of the Company since October 2003. Director of the following Ameren “controlled companies”: CILCORP; CILCO; UE; CIPS; AEG; IP. Age: 58. President of Energy Global, Inc., a consulting firm which specializes in corporate development, diversification and government relations strategies for energy companies. From 2002 to 2004, Dr. Jackson served as Managing Director of FE Clean Energy Group, a global private equity management firm that invests in energy companies and projects in Central and Eastern Europe, Latin America and Asia. From 1985 to 2001, Dr. Jackson was President of a consulting firm that advised energy companies on corporate development and diversification strategies and national and international governmental institutions on energy policy. From 1985 to 1995, she was Chief of Staff of the Coal Industry Advisory Board, which was established by the Paris-based International Energy Agency to obtain expert advice from industry executives on strategies for reducing dependence on oil. From 1978 to 1985, she held corporate planning, business development and international sales and marketing positions at Peabody Holding Company, Inc. Dr. Jackson is a past Deputy Chairman of the Federal Reserve Bank of St. Louis. Director of the Company since February 2005. Other directorships: Atlas Pipeline Partners, L.P. Age: 59.
		JAMES C. JOHNSON Vice President, Corporate Secretary and Assistant General Counsel of The Boeing Company, an aerospace and defense firm. Mr. Johnson joined The Boeing Company in May 1998 and has served in his current position since December 2003. Prior to joining The Boeing Company, Mr. Johnson served as Vice President, Secretary and Assistant General Counsel of Northrop Grumman Corporation from 1988 to 1998. Age: 53.
		RICHARD A. LIDDY Retired Chairman of GenAmerica Financial Corporation, which provides life, pension, annuity and related insurance products and services. Mr. Liddy served as Chairman of the Board of GenAmerica Financial from September 2000 to April 2002. He also served as Chairman of the Board of Reinsurance Group of America from May 1993 to April 2002. Mr. Liddy was President of GenAmerica Financial from May 1988 to September 2000 and Chief Executive Officer of General American Life Insurance Company from May 1992 to September 2000. In January 2000, while Mr. Liddy served as President of GenAmerica Financial Corporation, GenAmerica sold its mutual holding company to Metropolitan Life Insurance Company. At the request of the Missouri State Insurance Department, a receiver was appointed in order to oversee the equitable distribution of proceeds to policyholders. Director of the Company since 1997. Director of CILCORP, an Ameren subsidiary. Other directorships: Brown Shoe Company, Inc.; Ralcorp Holdings Inc.; Energizer Holdings, Inc. Age: 70.
		GORDON R. LOHMAN Retired Chairman and Chief Executive Officer of AMSTED Industries Incorporated, Chicago, Illinois, a manufacturer of railroad, construction, and general industrial products. Mr. Lohman was elected President of AMSTED Industries in 1988 and became Chief Executive Officer in 1990 and Chairman in 1997. He retired in 1999. Director of the Company since 1997. Other directorships: Acco Brands Corporation; Fortune Brands, Inc. Age: 71.

		RICHARD A. LUMPKIN Chairman of Consolidated Communications Holdings, Inc., a telecommunications holding company. Mr. Lumpkin assumed his present position as Chairman of Consolidated Communications Holdings, Inc. upon completion of a corporate reorganization in July 2005 as part of an initial public offering. Prior to the reorganization, Mr. Lumpkin had served as Chairman of Consolidated Communications, Inc., since January 1, 2003 upon the acquisition of the former Illinois Consolidated Telephone Company from McLeodUSA Incorporated. Prior to the acquisition, Mr. Lumpkin had served as President of Illinois Consolidated Telephone Company since 1977 and also Chairman and Chief Executive Officer since 1990. As a result of a September 1997 merger, he also had served as Vice Chairman of McLeodUSA Incorporated until April 2002. In order to complete a recapitalization, McLeodUSA Incorporated filed, in January 2002, a pre-negotiated plan of reorganization through a Chapter 11 bankruptcy petition filed in the United States Bankruptcy Court for the District of Delaware. In April 2002, McLeodUSA Incorporated’s plan of reorganization became effective and it emerged from Chapter 11 protection. Director of the Company since 1997. Other directorships: Consolidated Communications Holdings, Inc.; First Mid-Illinois Bancshares, Inc.; First Mid-Illinois Bank & Trust, N.A. Age: 70.
		CHARLES W. MUELLER Retired Chairman and Chief Executive Officer of the Company, UE and Ameren Services and retired Chairman of CILCORP and CILCO. Mr. Mueller began his career with UE in 1961 as an engineer and held various positions with UE and other Ameren subsidiaries during his employment. He was elected President of UE in 1993 and Chief Executive Officer in 1994. Mr. Mueller was elected Chairman, Chief Executive Officer and President of Ameren upon its formation in 1997. He relinquished his position as President of Ameren, UE and Ameren Services in 2001. He was elected Chairman of CILCORP and CILCO in January 2003. Mr. Mueller retired as an officer of Ameren and its subsidiaries on December 31, 2003. Director of the Company since 1997. Mr. Mueller is a past Chairman and former director of the Federal Reserve Bank of St. Louis. Other directorships: Angelica Corporation. Age: 67.
		DOUGLAS R. OBERHELMAN Group President of Caterpillar Inc., a maker of construction and mining equipment, diesel and natural gas engines and industrial gas turbines. Mr. Oberhelman joined Caterpillar in 1975. He held a variety of positions, including senior finance representative based in South America for Caterpillar Americas Co. and region finance manager and district manager for Caterpillar’s North American Commercial Division, before his appointment as managing director and vice general manager of strategic planning at Shin Caterpillar Mitsubishi Ltd. (Tokyo) in 1991. He was elected a Vice President in 1995 when he served as Caterpillar’s Chief Financial Officer. In 1998, he accepted leadership of Caterpillar’s Engine Products Division. Mr. Oberhelman was elected a Group President in 2001 with responsibility for Caterpillar’s corporate financial, audit and compliance, and legal divisions. Additionally, his responsibilities include the world wide operations, sales and marketing for Caterpillar’s diesel engine and power systems businesses. Director of the Company since 2003. Other directorships: South Side Bank (in Peoria, Illinois). Age: 52.

		GARY L. RAINWATER Chairman, Chief Executive Officer and President of the Company, UE, CILCORP and Ameren Services and Chairman and Chief Executive Officer of CIPS, CILCO and IP. Mr. Rainwater began his career with UE in 1979 as an engineer and has held various positions with UE and other Ameren subsidiaries during his employment. He was elected President and Chief Operating Officer of the Company, UE and Ameren Services in 2001. Effective January 1, 2004, Mr. Rainwater was elected to serve as Chairman and Chief Executive Officer of the Company, UE and Ameren Services in addition to his position as President. At that time, he was also elected Chairman of CILCORP and CILCO in addition to his position as Chief Executive Officer and President of those companies which he assumed in 2003. In September 2004, upon Ameren’s acquisition of IP, Mr. Rainwater was elected Chairman, Chief Executive Officer and President of IP. He currently holds the position of Chairman and Chief Executive Officer of CIPS, CILCO and IP after relinquishing his position as President in October 2004. Director of the Company since 2003. Director of the following Ameren subsidiaries: CILCORP; CILCO; UE; CIPS; AEG; IP. Age: 59.
		HARVEY SALIGMAN Partner of Cynwyd Investments, a family real estate partnership. Mr. Saligman has been a partner of Cynwyd Investments since 1996. He also served in various executive capacities in the consumer products industry for more than 35 years. Director of the Company since 1997. Director of the following Ameren “controlled companies” until April 2004: CILCORP; CILCO; UE; CIPS; AEG. Age: 66.67.
		PATRICK T. STOKES President and Chief Executive Officer of Anheuser-Busch Companies, Inc., a holding company,and Chairman and Chief Executive Officer of Anheuser-Busch, Incorporated, a producer and distributor of beer. Mr. Stokes has been affiliated with Anheuser-Busch since 1969, was elected President of Anheuser-Busch, Incorporated in 1990, and has served in his current positions since 2002. From 2000 to 2002, he served as Senior Executive Vice President of Anheuser-Busch Companies, Inc. Director of the Company since December 2004. Other directorships: Anheuser-Busch Companies, Inc.,; U.S. Bancorp. Age: 62.63.

YOUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE FOR THE ELECTION OF THESE DIRECTOR NOMINEES.

Board Structure, Director Compensation and Corporate Governance

Board Structure

Board and Committee Meetings and Annual Meeting Attendance – During 2005, the Board of Directors met seven times. All directors attended or participated in 75 percent or more of the aggregate number of meetings of the Board and the Board Committees of which they were members.

The Company has adopted a policy to encourage Board members to attend the annual meeting of shareholders. At the 2005 annual meeting, all of the then incumbent directors were in attendance.

Age Policy – Directors who attain age 72 prior to the date of an annual meeting cannot be designated as a nominee for election at that annual meeting. In addition, the eligibility of former employees, except for an employee who has been elected Chief Executive Officer of Ameren, UE or CIPS, is limited to the date upon which they retire, resign or otherwise sever active employment with the respective company.

Board Committees – The Board of Directors has a standing Audit Committee, Executive Committee, Human Resources Committee, Nominating and Corporate Governance Committee, Nuclear Oversight Committee, and Public Policy Committee, the members of which are identified below. The Audit Committee, Human Resources Committee and Nominating and Corporate Governance Committee are comprised entirely of non-management directors, each of whom the Board of Directors has determined to be “independent” as defined by the relevant provisions of the Sarbanes-Oxley Act of 2002, the New York Stock Exchange (“NYSE”) listing standards and the Company’s Policy Regarding Nominations of Directors.

Audit Committee

The Public Policy Committee, formerly the Contributions Committee, held four meetings in 2005. The Public Policy Committee is responsible for reviewing and overseeing the Company’s policies, practices and performance with respect to corporate citizenship and public affairs considerations affecting the Company’s relationship and reputation with its key constituents. It also makes policies and recommendations with respect to charitable and other contributions.

Executive Committee

The Executive Committee has such duties as may be delegated to it from time to time by the Board and has authority to act on most matters concerning management of the Company’s business during intervals between Board meetings. The Executive Committee held three meetings in 2005.

Nuclear Oversight Committee

The Nuclear Oversight Committee provides Board-level oversight of the Company’s nuclear power facility as well as long-term plans and strategies of Ameren’s nuclear power program and makes appropriate reports to the Board. The Nuclear Oversight Committee held four meetings in 2005.

The Nominating and Corporate Governance Committee is responsible for the nomination of directors and the Company’s corporate governance practices. More specifically, the Committee is

responsible for: (1) adopting policies and procedures for identifying and evaluating director nominees, including nominees recommended by shareholders; (2) identifying and evaluating individuals qualified to become Board members, considering director candidates recommended by shareholders and recommending that the Board select the director nominees for the next annual meeting of shareholders; (3) reviewing the Board’s policy for director compensation and benefits; (4) establishing a process by which shareholders will be able to communicate with members of the Board; and (5) developing and recommending to the Board corporate governance guidelines applicable to the Company. The Company normally does not pay any third party a fee to identify or evaluate or assist in identifying or evaluating potential director nominees and did not do so with regard to the nominees recommended for election in this proxy statement. The Nominating and Corporate Governance Committee also has oversight responsibilities with respect to the Company’s code of business conduct (referred to as its Corporate Compliance Policy) and its Code of Ethics for Principal Executive and Senior Financial Officers. See “Corporate Governance” below. The Nominating and Corporate Governance Committee held five meetings in 2004.

The Nominating and Corporate Governance Committee will consider director nominations from shareholders in accordance with the Company’s Policy Regarding Nominations of Directors, a copy of which is attached hereto as Appendix B. The Board adopted changes to this policy in February 2005 to take into account recently adopted revisions to the rules of the NYSE. Briefly, the Committee will consider as a candidate any director of the Company who has indicated to the Committee that he or she is willing to stand for re-election as well as any other person who is recommended by any shareholders of the Company who provide the required information and certifications within the time requirements, as set forth in Section 1 of the Policy Regarding Nominations of Directors. The Committee may also undertake its own search process for candidates and may retain the services of professional search firms or other third parties to assist in identifying and evaluating potential nominees.

In considering a potential nominee for the Board, shareholders should note that in selecting candidates, the Nominating and Corporate Governance Committee endeavors to find individuals of high integrity who have a solid record of accomplishment in their chosen fields and who display the independence to effectively represent the best interests of all shareholders. Candidates are selected for their ability to exercise good judgment, and to provide practical insights and diverse perspectives. Although the Committee may seek candidates that have different qualities and experiences at different times in order to maximize the aggregate experience, qualities and strengths of the Board members, nominees for each election or appointment of directors will be evaluated using a substantially similar process and under no circumstances will the Committee evaluate nominees recommended by a shareholder of the Company pursuant to a process substantially different than that used for other nominees for the same election or appointment of directors.

The Nominating and Corporate Governance Committee considers the following qualifications at a minimum in recommending to the Board potential new Board members, or the continued service of existing members:

Other than the foregoing, there are no stated minimum criteria for director nominees, although the Nominating and Corporate Governance Committee may also consider such other factors as it may deem are in the best interests of the Company and its shareholders. The Nominating and Corporate Governance Committee does, however, believe it appropriate for at least one member of the Board to meet the criteria for an “audit committee financial expert” as defined by SEC rules.

Contributions Committee

The Contributions Committee makes policies and recommendations with respect to charitable and other contributions. The Contributions Committee held three meetings in 2004. Effective after the Annual Meeting, the Contributions Committee will be renamed the Public Policy Committee and will assume the additional functions of reviewing and overseeing the Company’s policies, practices and performance with respect to corporate citizenship and public affairs considerations affecting the Company’s relationship and reputation with its key constituents.

Executive Committee

The Executive Committee has such duties as may be delegated to it from time to time by the Board and has authority to act on most matters concerning management of the Company’s business during intervals between Board meetings. The Executive Committee held five meetings in 2004.

Nuclear Oversight Committee

The Nuclear Oversight Committee was formed by the Company’s Board of Directors in December 2004 to provide Board-level oversight of the Company’s nuclear power facility as well as long-term plans and strategies of Ameren’s nuclear power program and make appropriate reports to the Board. The Nuclear Oversight Committee did not meet in 2004.

Executive Sessions of Non-management Directors – The non-management directors meet privately in executive sessions to consider such matters as they deem appropriate, without management being present, as a routinely scheduled agenda item for every Board meeting. An executive session including only independent directors as defined by the NYSE listing standards is held at least once a year. During 2004, all non-management directors were independent, except Mr. Mueller. Mr. MacCarthy served as Lead Director presiding at such executive sessions during 2004 and will continue to do so until his retirement at the Annual Meeting. Mr. Lohman has been chosen to

replace Mr. MacCarthy as Lead Director, subject to his election as a director at the Annual Meeting.

Executive Sessions of Non-management Directors – The non-management directors meet privately in executive sessions to consider such matters as they deem appropriate, without management being present, as a routinely scheduled agenda item for every Board meeting. An executive session including only independent directors as defined by the NYSE listing standards is held at least once a year. During 2005, all non-management directors were independent, except Charles W. Mueller. Gordon R. Lohman served as Lead Director presiding at such executive sessions during 2005 from the time of his appointment on April 26, 2005. The Lead Director’s duties include convening and chairing meetings of the non-management directors in executive session; convening and chairing meetings of the independent directors in executive session; presiding at all meetings of the Board at which the Chairman is not present, including executive sessions of the non-management directors and independent directors; regularly polling the non-management directors for advice on agenda items for meetings of the Board; serving as a liaison between the Chairman and Chief Executive Officer and the non-management directors; collaborating with the Chairman and Chief Executive Officer in developing the agenda for meetings of the Board and approving such agendas; approving information that is sent to the Board; collaborating with the Chairman and Chief Executive Officer and the chairpersons of the standing committees in developing and managing the schedule of meetings of the Board and approving such schedules; collaborating with the Chairman and Chief Executive Officer in developing the budget of the Board; and if requested by the major shareholders, ensuring that he is available for consultation and direct communication.

Director Compensation

Fees and Stock Awards – In 2004,2005, the compensation for each director who is not an employee of the Company consisted of the following:

Directors who are employees of the Company do not receive compensation for their services as a director.

The following table sets forth the compensation paid to non-management directors duringfor fiscal year 2004,2005, other than reimbursement for travel expenses.

Deferred Compensation Plan Participation – An optional deferred compensation plan available to directors permits non-management directors to defer all or part of their annual cash retainers and meeting fees. The minimum amount that can be deferred in any calendar year is $3,500. Deferred amounts, plus an interest factor, are used to provide payout distributions following completion of Board service and certain death benefits. Deferred amounts earn interest at 150 percent of the average Mergent’s Seasoned AAA Corporate Bond Yield Index (“Mergent’s Index,” formerly called Moody’s Index) until the participant director retires or dies. After the participant director retires or dies, the deferred amounts earn interest at the average Mergent’s Index rate. For 2004,2005, the average Mergent’s Index rate was 5.675.63 percent, 150 percent of which was 8.518.46 percent. A participant director may choose to receive the deferred amounts at retirement in a lump sum payment or in installments over five, ten or fifteen years. If a participant director revokes the election to defer retainers and fees, deferred amounts will be distributed in a lump sum with all interest credited to the participant’s account forfeited. Costs of the deferred compensation plan are expected to be recovered through the purchase of life insurance on the participants, with the Company being the owner and beneficiary of the insurance policies. Directors Greenwalt, Hays,policies.Directors Liddy, Lohman, Lumpkin, MacCarthy, Oberhelman, Saligman and SaligmanStokes deferred

amounts under the plan in 2004.In2005. In the event a participating director resigns from the Board of Directors prior to becoming eligible for retirement and after the occurrence of a change in control (as defined in such plan), the balance in such director’s deferral account, including interest payable at 150 percent of the average Mergent’s Index, shall be distributed in a lump sum to the director within 30 days after the date the director resigns.

Stock Ownership GuidelinesGuideline – In August 2004, the Company’s Board of Directors adopted a voluntary stock ownership guideline applicable to all of its directors. Under this guideline, for directors within five years of its adoption or within five years after initial election to the Board, all then current directors are highly encouraged to own Company Common Stock equal

in value to at least three times their base cash annual retainer and to hold such amount of stock throughout their directorships. New directors are encouraged to meet this level of stock ownership within five years after their initial election to the Board.

Corporate Governance

Corporate Governance Guidelines and Policies, Committee Charters and Codes of Conduct – The Board of Directors has adopted Corporate Governance Guidelines, a Policy Regarding Nominations of Directors, a Shareholder Communications Policy and written charters for its Audit Committee, Human Resources Committee, Nominating and Corporate Governance Committee, and Nuclear Oversight Committee, and Public Policy Committee. The Board of Directors also has adopted the Company’s code of business conduct (referred to as its Corporate Compliance Policy) applicable to all of the Company’s directors, officers and employees and the Company’s Code of Ethics for Principal Executive and Senior Financial Officers. These documents and other items relating to the governance of the Company, including the Company’s corporate strategic planning process and the Board’s involvement in such process, can be found on the Company’s website athttp://www.ameren.com. These documents are also available in print free of charge to any shareholder who requests them from the Office of the Company’s Secretary.

Director Independence – The Board of Directors has determined, after careful review, that all director nominees, except Messrs.Charles W. Mueller and Gary L. Rainwater, are independent as defined by the relevant provisions of the Sarbanes-Oxley Act of 2002, the NYSE listing standards and the Company’s Policy Regarding Nominations of Directors.

Under the Company’s Policy Regarding Nominations of Directors, an “independent director” is one who:

For purposes of determining a “material relationship,” the following standards are utilized:

For purposes of these independence standards, (i) immediate family members of a director include the director’s spouse, parents, children, siblings, mother- and father-in-law, sons- and daughters-in-law, and brothers- and sisters-in-law and anyone (other than domestic employees) who shares the director’s home and (ii) the term “primary business affiliation” means an entity of which the director is a principal/executive officer or in which the director holds at least a 5 percent equity interest.

Certain Relationships and Related Transactions – During 2004,2005, subsidiaries of Ameren were parties to certain business transactions with institutions related to directors and nominees. These transactions, which were principally related to the supply of regulated public utility energy services and non-regulated energy services, were done in the ordinary course of business, with terms and conditions the same or substantially the same as those prevailing for comparable transactions with non-affiliated persons. The Board of Directors has determined that these business transactions do not cause a material relationship to exist between the Company and a director or nominee as defined by the NYSE listing standards and the Company’s Policy Regarding Nominations of Directors.

Only Messrs.Douglas R. Oberhelman and Cornelius had a business relationshipsrelationship with the Company in 20042005 that areis required to be reported. Mr. Oberhelman is an executive officer of Caterpillar Inc. which purchases regulated public utility energy services and non-regulated energy services from certain of the Company’s subsidiaries (primarily CILCO, Ameren Energy Marketing Company, IP and UE) and sells and leases equipment to and provides maintenance and training services for some of the Ameren subsidiaries. During 2004,2005, revenues from energy sales by Ameren subsidiaries to Caterpillar

aggregated approximately $41$46.8 million excluding revenues from the supply of regulated public utility services and revenues based on competitive bid transactions. Payments made during 20042005 by Ameren subsidiaries to Caterpillar for the purchase or lease of equipment aggregated approximately $1.8 million and$146,000, for the repurchase of energy aggregated approximately $84,000.$80,000 and for maintenance and training services aggregated approximately $1.3 million. These transactions, many of which are for multiple year terms, were entered into in the ordinary course of business on an arms length basis. The total of all payments made by the Company’s subsidiaries to Caterpillar and payments received by the Company’s subsidiaries from Caterpillar during 20042005 (including payments related to the supply of regulated public utility services and payments related to competitive bid transactions) did not exceed 2 percent of Caterpillar’s 20042005 consolidated revenues of approximately $30.25$36.339 billion. In addition, the total of all payments made by Ameren subsidiaries to Caterpillar during 2004 were2005 was less than 2 percent of Ameren’s 20042005 consolidated revenues of approximately $5.2$6.78 billion.

Mr. Cornelius has served as an advisor to the Company’s Board of Directors since his retirement as a director in April 2004. He received cash compensation of $22,336 for his service as an advisor in 2004. See the table under “Director Compensation” above for his total director Caterpillar and advisor compensation inAmeren transactions also did not exceed these 2 percent thresholds during 2003 and 2004.

In addition to the above business relationships, certain of the Company’s directors and executive officers had reportable family relationships in 2004.2005. Charles W. Mueller is the father of Michael G. Mueller, President of the Company’s wholly-owned indirect subsidiary, Ameren Energy Fuels and Services Company and a Vice President of Ameren Services, for which he received in 20042005 aggregate salary, bonus and other compensation of $314,887$345,818 and a restricted stock award of 1,7261,640 shares of Ameren Common Stock, valued at $79,983$83,984 based on the closing market price of $46.34$51.21 per share on February 13, 2004,11, 2005, the date the restricted stock was awarded. See Footnotes 34 and 45 to the “Summary Compensation Table” under “Executive Compensation” below for information regarding restricted stock awards and other compensation, respectively. Another son of Mr. Mueller, Charles R. Mueller, is employed by recently acquired IP as a supervising engineer, for which he received aggregate salary, bonus and bonusother compensation of $141,088$137,825 for 2004.2005. A sister of Gary L. Rainwater, Patricia A. Fuller, is employed by Ameren Services as a supervisorhealth and welfare consultant in its Human Resources Function, for which she received aggregate salary, bonus and bonusother compensation of $99,480$104,436 for 2004.2005. Wendy C. Brumitt, a daughter of Thomas R. Voss, Executive Vice President and Chief Operating Officer of the Company and an executive officer of various Company subsidiaries, is employed by UE as an engineer at its Callaway nuclear plant, for which she received aggregate salary, bonus and bonusother compensation of $71,047$85,469 for 2004.2005. Gary L. Weisenborn, a brother of Dennis W. Weisenborn, a Vice President of various Company subsidiaries, is employed by UE as a power plant superintendent for which he received aggregate salary, bonus and bonusother compensation of $127,178$132,870 for 2004.2005. Diana L. Weisenborn, the wife of Gary L. Weisenborn and sister-in-law of Dennis W. Weisenborn, is employed by Ameren Services as an executive secretary, for which she received aggregate salary, bonus and bonusother compensation of $60,422$68,095 for 2004.2005. Jennifer Curtis, a daughter of Craig D. Nelson, a Vice President of various Company subsidiaries, is employed by CILCO as a supervisor in its Credit Department,for customer accounts, for which she received aggregate salary, bonus and other compensation of $75,866 for 2005. Susan M. Prebil, wife of William J. Prebil, a Vice President of various Company subsidiaries, was employed by CILCO as a settlement specialist during a portion of 2005 for which she received salary and other compensation of $4,056. In 2005, Mrs. Prebil terminated her 28 year employment with CILCO pursuant to a voluntary separation program and in that connection received aggregate compensation of $103,644. David E. Boll, a brother-in-law of Robert F. Neff, a Vice President of Ameren Energy Fuels and Services Company, is employed by Ameren Services as a managing supervisor of mechanical engineering for which he received aggregate salary, bonus and other compensation of $62,366$111,401 for 2004.2005. Ricky W. Rogers, a brother-in-law of Timothy E. Herrmann, a Vice President of UE as of January 1, 2006, is employed by UE as substation traveling operator for which he received aggregate salary, bonus and other compensation of $80,715 for 2005.

Shareholder Communications with Directors – The non-management directors of the Board of Directors have adopted a policy for shareholders to send communications to the Board. Shareholders who desire to communicate with the Company’s directors or a particular director may write to: Ameren

Corporation Board of Directors, c/o Manager of Investor Relations, 1901 Chouteau Avenue, MCMail Code 202, St. Louis, Missouri 63103. Communications received from shareholders to the Board of Directors will be reviewed by the Manager of Investor Relations and if they are relevant to, and consistent with, the Company’s operations and policies that are approved by all non-management members of the Board, they will be forwarded to the Lead Director or applicable Board member or members as expeditiously as reasonably practicable.

Annual Assessment of Board, and Board Committee and Individual Director Performance – The Board reviews its own performance, structure and processes in order to assess how effectively it is functioning. This assessment is implemented and administered by the Nominating and Corporate Governance Committee through an annual Board self-evaluation survey. The views of individual directors are collected by the Secretary of the Company and the Chairman of the Nominating and Corporate Governance Committee and summarized for consideration by the full Board. In addition, each of the Audit Committee, Human Resources Committee, and the Nominating and Corporate Governance Committee, Nuclear Oversight Committee, and Public Policy Committee of the Board conduct an annual self evaluation of its performance. Individual directors are also asked annually to assess each other’s performance through a director peer assessment.

Item (2):     Approval of the 2006 Omnibus Incentive Compensation Plan

The Board’s Nuclear OversightBoard is requesting that shareholders vote in favor of adopting the Ameren Corporation 2006 Omnibus Incentive Compensation Plan (the “Plan”), which was approved by the Board of Directors on February 10, 2006, subject to shareholder approval. The Plan has been established to replace, on a prospective basis, the Ameren Corporation Long-Term Incentive Plan of 1998 (the “Prior Plan”) which was previously approved by shareholders and expires on April 1, 2008. If the Plan is approved by shareholders, no new grants will be made from the Prior Plan. Any awards previously granted under the Prior Plan shall continue to vest and/or be exercisable in accordance with their original terms and conditions.

The proposed Plan is intended to develop employees’ sense of proprietorship and personal involvement in the development and financial success of the Company, and to encourage members of the Company’s Board of Directors to devote their best efforts to the business of the Company, thereby advancing the interests of the Company and its shareholders. In order to build a stable and experienced management team, the Company seeks to maintain and strengthen these individuals’ desire to remain with the Company as well as to attract able individuals to become employees or serve as directors. As with the Prior Plan, the ultimate goal of the Plan is to encourage those individuals who are and will be responsible for the Company’s future growth and continued success to have a greater personal financial investment in the Company through ownership of its Common Stock.

This Plan retains many of the features of the Prior Plan plus provides new features that will allow greater flexibility, such as performance units denominated in dollars, restricted stock units, cash-based awards and other stock-based awards. As with the Prior Plan, all awards for employees can only be made pursuant to the authority of the Human Resources Committee (the “Committee”) of the Board and Public Policywith respect to non-management directors, all awards can only be made pursuant to the authority of the Board.

Key features of the Plan are described below, but are qualified in their entirety by reference to the full text of the Plan attached as Appendix B to this proxy statement:

that on or after such date cease for any reason to be subject to such awards, but subject to adjustment upon the occurrence of various corporate events as described in the Plan), all of which may be issued pursuant to incentive stock options (ISOs);

-

Net sales or revenue growth;

The Committee will begin conductingdetermine whether the performance targets or goals that have been chosen for a particular performance award have been met and may provide in an award that any evaluation of performance may include or exclude any of the following that are objectively determinable and that occur during the performance period to which the award is subject: asset write-downs, litigation, claim judgments, or settlements; the effect of changes in tax laws, accounting principles, or other laws or provisions affecting reporting results; any reorganization and restructuring programs; extraordinary nonrecurring items as described in Accounting Principles Board Opinion No. 30 and/or in management’s discussion of financial condition and results of operations appearing in the Company’s annual report to shareholders or Annual Report on Form 10-K for the applicable year; acquisitions or divestitures; and foreign exchange gains and losses.

Awards that are designed to qualify as performance-based compensation may not be adjusted upward. However, the Committee has the discretion to adjust these awards downward. In addition, the

Committee has the discretion to make awards that do not qualify as performance-based compensation. Generally, awards may be paid in the form of cash, shares of common stock, or in any combination, as determined by the Committee.

Performance awards granted by the Committee under the Plan are intended to qualify for the “performance based compensation” exception from the $1 million cap on deductibility of executive compensation imposed by Section 162(m) of the Internal Revenue Code of 1986, as amended (the “Code”). Because the Company has retained the discretion to change specific performance targets, shareholder re-approval of the Plan will be required in the future under regulations issued pursuant to Section 162(m) of the Code, currently every five years. Thus, absent additional shareholder approval, no performance award may be granted under the Plan subsequent to the Company’s annual meeting of shareholders in 2011.

Administration

The Plan will be administered by the Committee. The Committee shall have full and exclusive discretionary authority, subject to the provisions of the Plan, to establish rules and regulations necessary for the proper administration of the Plan. All actions taken and all interpretations and determinations made by the Committee shall be final and binding.

Eligibility

Employees and non-management directors of the Company or any of its subsidiaries or affiliates are eligible to receive awards under the Plan. From time to time, the Committee (or as to non-management directors, the Board) will determine who will be granted awards, the number of shares subject to such grants and all other terms of awards.

While all employees are eligible to receive awards under the Plan, the Committee currently expects that approximately 180 employees will initially participate in the Plan. The Board currently expects that all non-management directors, of which there will be 10 if all such nominees are elected, will also initially participate in the Plan.

As described above under “Board Structure, Director Compensation and Corporate Governance – Director Compensation –Fees and Stock Awards,” each non-management director is currently awarded on an annual self evaluationbasis 1,000 shares of the Company’s Common Stock and, upon a non-management director’s initial election to the Board, 1,000 shares of the Company’s Common Stock. The Board expects that these awards will be continued under the Plan, and any change would be determined by the Board of Directors in the future. In addition, as described below under “Initial Awards under Plan to Named Executive Officers,” the Board has awarded, subject to shareholder approval, certain long-term incentive compensation awards under the Plan to the Named Executive Officers described below, in lieu of awards under the Prior Plan for the period commencing January 1, 2006.

Change of Control

Awards under the Plan are expected to be generally subject to special provisions upon the occurrence of a “change of control” as defined in the Change of Control Plan (as defined below “Arrangements With Named Executive Officers – Change of Control Severance Plan”) (in certain cases whether or not the employee has a qualifying termination of employment). The Committee, depending upon market practice, may provide in awards made under the Plan that if a “change of control” occurs (1) all outstanding stock options, and other awards under which the participant may have rights, the exercise of which is restricted or limited, may become fully exercisable, (2) all restrictions or limitations,

including risks of forfeiture and deferrals, on restricted stock or other awards subject to restrictions or limitations under the Plan may lapse and (3) all performance goals applicable to performance awards, and any other conditions to payment of any awards under which payment is subject to conditions may be deemed to be achieved or fulfilled and may be waived by the Company.

Upon a “change of control” which occurs on or before December 31, 2008 in which the Company ceases to exist or is no longer publicly trading on the NYSE or the NASDAQ Stock Market, all of the initial performance share unit awards granted under the Plan, subject to shareholder approval, as described below under “Initial Awards Under Plan to Named Executive Officers” (the “target number”), together with dividends accrued thereon, shall be converted to nonqualified deferred compensation in an initial amount equal to the value of one share of the Company’s Common Stock multiplied by the sum of the target number plus dividends accrued thereon, computed as provided in the award agreement. Interest on the nonqualified deferred compensation shall accrue based on the prime rate, computed as provided in the award agreement. If the participant remains employed with the Company or its successor until December 31, 2008, the nonqualified deferred compensation, plus interest will be paid to the participant as a lump sum on such date. If the participant remains employed with the Company or its successor until his death or disability which occurs before December 31, 2008, the participant or his designee will immediately receive the nonqualified deferred compensation, plus interest, upon such death or disability. If the participant is involuntarily terminated (which includes a voluntary termination for Good Reason (as defined in the Change of Control Plan) (collectively, a “qualifying termination”)) before December 31, 2008, the participant will immediately receive the nonqualified deferred compensation, plus interest upon such termination. If the participant terminates employment before December 31, 2008 other than as described in the two immediately preceding sentences, the nonqualified deferred compensation, plus interest is forfeited. Upon such a “change of control” that occurs after December 31, 2008, the participant will receive an immediate distribution of cash equal to the value of one share of the Company’s Common Stock multiplied by the number of earned performance share units, computed as provided in the award agreement.

With respect to the initial performance share unit awards, if there is a “change of control” but the Company continues in existence and remains a publicly traded company on the NYSE or the NASDAQ Stock Market, the performance share units will pay out upon the earliest to occur of the following: (i) January 1, 2011, (ii) the participant’s death, (iii) if the participant becomes disabled or retires during the performance period, January 1, 2009, (iv) if the participant becomes disabled or retires after the performance period, upon the participant’s disability or retirement, respectively, (v) if the participant experiences a qualifying termination during the two-year period following the “change of control” and the termination occurs prior to January 1, 2009, all of the performance share units the participant would have earned if such participant remained employed until December 31, 2008 will vest on such date and such vested performance share units will be paid in shares of the Company’s Common Stock as soon as practicable thereafter, and (vi) if the participant experiences a qualifying termination during the two-year period following the “change of control” but the termination occurs after December 31, 2008, the participant will receive an immediate distribution of the earned shares of the Company’s Common Stock.

Federal Income Tax Consequences

The following discussion summarizes certain material federal income tax consequences of the issuance and receipt of awards under the Plan under the law as in effect on the date of this proxy statement. The summary does not purport to cover all federal employment tax or other federal tax consequences that may be associated with the Plan, nor does it cover state, local, or non-U.S. taxes.

Incentive Stock Options (ISO)

An employee generally realizes no taxable income upon the grant or exercise of an ISO. However, the exercise of an ISO may result in an alternative minimum tax liability to the employee. With some

exceptions, a disposition of shares purchased under an ISO within two years from the date of grant or within one year after exercise produces ordinary income to the optionee equal to the value of the shares at the time of exercise less the exercise price. The same amount is deductible by the Company as compensation, provided that the Company reports the income to the employee. Any additional gain recognized in the disposition is treated as a capital gain for which the Company is not entitled to a deduction. If the employee exercises an ISO and satisfies the holding period requirements, the Company may not deduct any amount in connection with the ISO. If a sale or disposition of shares acquired with the ISO occurs after the holding period, the employee will recognize long-term capital gain or loss at the time of sale equal to the difference between proceeds realized and the exercise price paid.

In general, an ISO that is exercised by the optionee more than three months after termination of employment is treated as an NQSO. ISOs are also treated as NQSOs to the extent they first become exercisable by an individual in any calendar year for shares having a fair market value (determined as of the date of grant) in excess of $100,000.

Non-Qualified Stock Options (NQSO)

An optionee generally has no taxable income at the time of grant of an NQSO but realizes income in connection with exercise of the option in an amount equal to the excess (at the time of exercise) of the fair market value of shares acquired upon exercise over the exercise price. The same amount is deductible by the Company as compensation, provided that, in the case of an employee option, the Company reports the income to the employee. Upon a subsequent sale or exchange of the shares, any recognized gain or loss after the date of exercise is treated as capital gain or loss for which the Company is not entitled to a deduction.

Stock Appreciation Rights (SARS)

Generally, the recipient of a stand-alone SAR will not recognize taxable income at the time the stand-alone SAR is granted. If a participant receives the appreciation inherent in the SARs in cash, the cash will be taxed as ordinary income to the participant at the time it is received. If a participant receives the appreciation inherent in the SARs in shares, the spread between the then current market value and the base price will be taxed as ordinary income to the participant at the time it is received. In general, there will be no federal income tax deduction allowed to the Company upon the grant or termination of SARs. However, upon the settlement of an SAR, the Company will be entitled to a deduction equal to the amount of ordinary income the recipient is required to recognize as a result of the settlement.

Restricted Stock

The recipient of restricted stock will not recognize any taxable income for federal income tax purposes in the year of the award, provided the shares are subject to restrictions (that is, they are nontransferable and subject to a substantial risk of forfeiture). However, the recipient may elect under Section 83(b) of the Code to recognize compensation income in the year of the award in an amount equal to the fair market value of the shares on the date of the award (less the purchase price, if any, paid for such shares), determined without regard to the restrictions. If a Section 83(b) election is made, the capital gains/loss holding period for such shares commences on the date of the award. Any further change in the value of the shares will be taxed as a capital gain or loss only if and when the shares are disposed of by the recipient. If the recipient does not make a Section 83(b) election, the fair market value of the shares on the date the restrictions lapse will be treated as compensation income to the recipient and will be taxable in the year the restrictions lapse, and the capital gains/loss holding period for such shares will also commence on such date. Except as described under“Other Tax Matters”

below, the Company or one of its subsidiaries generally will be entitled to a deduction for compensation paid in the same amount treated as compensation income to the recipient.

Restricted Stock Units

No income generally will be recognized upon the award of restricted stock units. The recipient of a restricted stock unit award generally will be subject to tax at ordinary income rates on the market price of unrestricted shares on the date that such shares are transferred to the participant under the award (reduced by any amount paid, if any, by the participant for such restricted stock units), and the capital gains/loss holding period for such shares will also commence on such date.

Cash Awards

Cash awards are taxable income to the recipient for federal income tax purposes at the time of payment. The recipient will have compensation income equal to the amount of cash paid, and except as described under“Other Tax Matters” below, the Company will have a corresponding deduction for federal income tax purposes.

Performance Awards

A participant who receives a performance award will not recognize any taxable income for federal income tax purposes upon receipt of the award. Any shares received pursuant to the settlement of the award will be treated as compensation income received by the employee generally in the year in which the employee receives such shares. Upon selling the shares, the recipient will recognize a capital gain or loss in an amount equal to the difference between the sale price of the shares and the recipient’s tax basis of the shares. The Company generally will be entitled to a deduction for compensation paid in the same amount that is treated as compensation income to the recipient.

Other Tax Matters

The exercise by a participant of a stock option, the lapse of restrictions on restricted stock, or the deemed achievement or fulfillment of performance awards following the occurrence of a change of control, in certain circumstances, may result in (i) a 20 percent federal excise tax (in addition to federal income tax) to the participant on certain payments of shares resulting from such exercise or deemed achievement or fulfillment of performance awards or, in the case of restricted stock, on all or a portion of the fair market value of the shares on the date the restrictions lapse and (ii) the unavailability of a compensation deduction which would otherwise be allowable to the Company as explained above. Except for stock options and performance awards that meet the requirements of the Plan and are based on the performance measures described therein, the Company may not be eligible for a compensation deduction which would otherwise be allowable for compensation paid to any employee if, as of the close of the tax year, the employee is the chief executive officer of the Company or is among the four other highest compensated officers for that tax year for whom compensation is required to be reported to shareholders under the Securities Exchange Act of 1934, as amended, to the extent the total compensation paid to such employee exceeds $1,000,000.

Initial Awards Under Plan to Named Executive Officers

On February 10, 2006, the Committee recommended and the Company’s Board of Directors approved the issuance pursuant to the Plan of performance share units to the Named Executive Officers as defined below (see “Security Ownership – Security Ownership of Management”) as follows, subject to shareholder approval of the Plan: W. L. Baxter, 17,755; C. D. Naslund, 7,600; G. L. Rainwater, 55,928; S. R. Sullivan, 13,494; and T. R. Voss, 15,624. Each performance share unit

represents the right to receive a share of the Company’s Common Stock assuming certain performance criteria are achieved. The actual number of performance share units earned will vary from 0 percent to 200 percent of the target number of performance share units granted to each Named Executive Officer identified above, based on the Company’s three-year total shareholder return (“TSR”) relative to a utility peer group and continued employment during the three-year period. Once earned, performance share units continue to rise and fall in value with the Company’s Common Stock price for two years, at which time the performance share units are paid in the Company’s Common Stock. Dividends on performance share units will accrue and be reinvested into additional performance share units throughout the three-year performance share period. Dividends will be paid on a current basis during the two-year holdback period. Because these performance share units will be earned only if performance goals over performance periods are attained, the amounts, if any, that will be payable to the Named Executive Officers pursuant to the performance share unit awards described above are not determinable at this time.

Additional Information

Upon approval by the Company’s shareholders, the Plan will be effective on May 2, 2006 and will terminate on May 2, 2016, unless terminated earlier by the Board of Directors. The Board may amend the Plan as it deems advisable, except that it may not amend the Plan without shareholder approval where the absence of such approval would cause the Plan to fail to comply with any requirement of applicable law or regulation. Employees who will participate in the Plan in the future and the amounts of their allotments are to be determined by the Committee subject to any restrictions outlined in the Plan.

The Company expects that stock options and performance awards under the Plan will qualify as performance-based compensation that is exempt from the $1,000,000 annual deduction limit (for federal income tax purposes) of compensation paid by public corporations to each of the corporation’s chief executive officer and four other most highly compensated executive officers in 2005.each fiscal year, which limit is imposed by Section 162(m). Because of ambiguities and uncertainties as to the application and interpretation of Section 162(m) and the regulations issued thereunder, no assurance can be given, notwithstanding the Company’s efforts, that compensation intended by the Company to satisfy the requirements for deductibility under Section 162(m) will in fact do so.

The closing price per share on the NYSE of the Company’s Common Stock on February 1, 2006 was $51.21. The Company intends to register the shares issuable under the Plan under the Securities Act of 1933, as amended, after it receives shareholder approval.

The Board believes it is in the best long-term interests of both shareholders and employees of the Company to maintain a progressive stock-based incentive program in order to attract and retain the services of outstanding directors and personnel and to encourage such directors and personnel to have a greater financial investment in the Company. Although the success of the Company over the past eight years cannot be attributed solely to the adoption of the Prior Plan, the Board firmly believes it contributed to the Company’s success.

Passage of the proposal requires the affirmative vote of a majority of the shares entitled to vote on the proposal and represented in person or by proxy at the meeting at which a quorum is present.

YOUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE FOR THE APPROVAL OF THE AMEREN CORPORATION 2006 OMNIBUS INCENTIVE COMPENSATION PLAN.

Item (2)(3):    Ratification of the Appointment of Independent Auditors for the Fiscal Year Ending December 31, 20052006

The Company is asking theits shareholders to ratify the appointment of PricewaterhouseCoopers LLP (“PwC”) as the Company’s independent auditors for the fiscal year ending December 31, 2005.2006. PwC was appointed by the Audit Committee.

Although ratification by the shareholders is not required by law, the Board of Directors has determined that it is desirable to request approval of this selection by the shareholders. In the event the shareholders fail to ratify the appointment, the Audit Committee will consider this factor when making any determination regarding PwC. Even if the selection is ratified, the Audit Committee in its discretion may direct the appointment of a different independent accounting firm at any time during the year if it determines that such a change would be in the best interests of the Company and its shareholders.

Passage of the proposal requires the affirmative vote of a majority of the votes cast.shares entitled to vote on the proposal and represented in person or by proxy at the meeting at which a quorum is present.

YOUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE FOR THE RATIFICATION OF THE APPOINTMENT OF PWC AS INDEPENDENT AUDITORS FOR FISCAL YEAR ENDING DECEMBER 31, 2005.2006.

Item (3)(4):    Shareholder Proposal Relating to the StorageRequesting an Evaluation of Irradiated Fuel Rods ata 20-Year Extension of the Callaway Nuclear Plant Operating License

Proponents of the shareholder proposal described below notified the Company of their intention to attend the Annual Meeting to present the proposal for consideration and action. The names and addresses of the proponents and the number of shares they hold will be furnished by the Secretary of the Company upon receipt of any telephonic or written request for such information.

WHEREAS:

As long as the Callaway nuclear plant operates, it will continue generating radioactively and thermally hot, irradiated fuel rods. In order to replace some irradiated fuel rods every few years with new fuel rods, the irradiated rods must be transferred from the Reactor Vessel to the on-site Spent Fuel Pool for wet storage and cooling for at least five years. Callaway’s irradiated fuel rods have been accumulating in the fuel pool since 1986.

The US Nuclear Regulatory Commission has granted Ameren permission(NRC) issues 40-year operating licenses for commercial nuclear power plants, and allows these licenses to store far more irradiated rods in the Callaway fuel pool than had been intended in the pool’s initial design.

Irradiated fuel rods must be kept isolated from the biosphererenewed for hundreds of thousands ofan additional 20 years.

AccordingA nuclear power plant licensee seeking to a February 2001renew its original license must submit an application to the NRC study, even in a shutdown plant undergoing decommissioning, a spent fuel pool catastrophe could raise the risk of radiation-induced cancer as far away as 500 miles, and of fatalities from radiation poisoning near the plant. The risks from a fuel pool accident at an operating plant are at least as great.that:

In 2002

In July 2004Some licensees have already received 20-year extensions of their original 40-year licenses. A licensee is allowed to apply to renew its license within the U.S. Court of Appeals, D.C. Circuit, ruled that20 years prior to the EPA standard forlicense expiration. Because Ameren’s Callaway Plant in Missouri began operating in December 1984, its operating license is due to expire in 2024. Ameren is therefore allowed to apply to renew its license within the Yucca Mountain facility (that regulates radiation releases for 10,000 years) does not reflect the 1995 National Academy of Sciences finding that peak risks to public health “might occur tens to hundreds of thousands of years or even further into the future.”

The nuclear industry describes Yucca Mountain as one single site where all the nation’s irradiated fuel rods could be consolidated. However, capacity at Yucca Mountain is limited by law. Irradiated fuel rods

now being stored at reactors older than Callaway would have priority for disposal space. There may not be room for a sizable amount of Callaway’s fuel rods in this first national repository.

Since each nuclear power plant’s irradiated rods must be kept submerged in water at that plant’s site at least temporarily, highly radioactive rods will continue to be generated and stored at every operating plant nationwide as long as nuclear plants continue operating.current twenty years.

RESOLVED:

In light of heightened public safety concerns, shareholdersShareholders request that Ameren prepare a report, at reasonable cost, that outlines the current substantial radiation risksomitting confidential information, and available within six months of the interim storage2006 annual meeting, that discloses the company’s evaluation (pros and cons) of irradiated fuel rods at the Callaway Plant and that proposes measures to reduce those risks. A copyapplying for a twenty-year extension of the report, omitting proprietary and security information, should be available to shareholders on request by August 2005.Callaway’s current 40-year operating license.

SUPPORTING STATEMENT:

Ameren remains morally responsible and financially liable for Callaway, for seeking to secure its radioactive wastes, and for protecting its workers and the public into the indefinite future. We believe this study is essential for realistic and responsible economic and ethical planning.

YOUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE AGAINST ITEM (3).

The Board is of the opinion that the concerns about the potential risks of the interim storage of spent nuclear fuel at the Callaway Plant are not well grounded and thus developing information in the form requested is unnecessary and would increase expenses without commensurate increase in relevant information.

To the extent that concerns about the safety of irradiated fuel stored in spent fuel pools arises from the perceived risk of potential terrorist attacks against Callaway, such concerns are unfounded.

The Board believes that, considering the proprietary nature of the information requested, the extensive regulation of the Callaway Plant by the NRC and current evaluations by the NRC and the Office of Homeland Security, there are no reasons to make public additional studies of the safety of spent fuel stored at the facility. Additional expenditures for such information would be imprudent, and therefore the Board unanimously recommends voting AGAINST ITEM (3).

Passage of the proposal requires the affirmative vote of a majority of the votes cast.

Item (4):    Shareholder Proposal Requiring an Independent Chairman of the Company’s Board of Directors

The proponent of the shareholder proposal described below notified the Company of its intention to attend the Annual Meeting to present the proposal for consideration and action. The name and address of the proponent and the number of shares it holds will be furnished by the Secretary of the Company upon receipt of any telephonic or written request for such information.

RESOLVED:The shareholders of Ameren Corporation (“Company”) urge the Board of Directors to amend the Company’s by laws, effective upon the expiration of current employment contracts, to require that an independent director – as defined by the rules of the New York Stock Exchange (“NYSE”) – be its Chairman of the Board of Directors.

SUPPORTING STATEMENT

The recent waveWe believe there are concerns about extending the operating life of corporate scandalsthe Callaway nuclear power plant beyond the 40-year duration for which the plant was originally designed, including:

– A 2005 National Academy of Sciences report presents new information that even low doses of ionizing radiation may cause adverse genetic and other health effects. (“Health Risks from Exposure to Low Levels of Ionizing Radiation,” BEIR VII – Phase 2);

– Due to the retirement of experienced employees and the industry-wide shortage of trained replacement employees, working conditions at such companiesnuclear power plants may become increasingly dangerous. Recruitment may continue to be difficult because of more widespread recognition of radiation hazards;

– Geologic, economic, transportation and security concerns about the proposed Yucca Mountain, Nevada, high-level radioactive waste disposal facility have made the ultimate disposal of Callaway’s irradiated fuel rods uncertain. Political and capacity concerns at the Barnwell, South Carolina, low-level radioactive waste facility also make the disposition of Callaway’s low-level waste uncertain;

– Planned and accidental releases of radioactive waste from Callaway to the Missouri River and the atmosphere during an additional 20 years may impact upon the health of downstream and downwind residents;

– In addition to the costs of operating and maintaining nuclear power plants, utilities are faced with the expense of replacing many components and retrofitting others as Enron, WorldCom and Tyco has resulted in renewed emphasis on the importance of independent directors.plants age. For example, both the NYSE and the NASDAQ have adopted rulesafter only 20 years, Ameren had to replace massive, expensive steam generators that would require corporations that wish to be traded on themwere supposed to have a majoritylasted for the plant’s entire 40-year licensed operation. Such expenditures could add substantially to the cost of independent directors.generating electricity.

Unfortunately, having a majority of independent directors aloneAmeren remains morally responsible and financially liable for Callaway into the indefinite future. We believe this report is clearly not enoughessential for Ameren’s realistic and responsible, economic and ethical planning and for its accountability to prevent the type of scandals that have afflicted Enron, WorldCom and Tyco. All of these corporations had a majority of independent directors on their boards when the scandals occurred.its shareholders.

All of these corporations also had a Chairman of the Board who was also an insider, usually the Chief Executive Officer (“CEO”), or a former CEO, or some other officer. We believe that no matter how many independent directors there are on a board, that board is less likely to protect shareholder interests by providing independent oversight of the officers if the Chairman of that board is also the CEO, former CEO or some other officer of the company.

We respectfully urge the board of our Company to dramatically change its corporate governance structure and the public’s perception of it by having an independent director, as defined by the NYSE, serve as its Chairman.

YOUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE AGAINST ITEM (4).

The Board is of the opinion that the concerns about extending the operating license for the Callaway Plant are premature, unnecessary and would increase expenses without commensurate increase in relevant information.

recommendations of the 2005 National Academy of Sciences Report. The GEIS also evaluates the disposal of high and low level radioactive waste, the release of plant effluents, and accident risk. Consequently, a generic evaluation of the proponent’s concerns already exists.

Ameren’s Health and Safety Policy and Environmental Policy evidence the Company’s commitment to protecting its employees, the public and the environment. Ameren fulfills its commitment to safety and environmental compliance by maintaining a corporate culture that recognizes safety and environmental compliance and stewardship as measurable goals. Operating the Callaway Plant in a safe and environmentally sound manner is an important part of these policies. The Board of Directors believes it would not beestablished the Nuclear Oversight Committee to assist the Board in the best interestsproviding oversight of the CompanyCallaway Plant’s operations (including safety and its shareholders to adopt a By-Law provision that would require thatenvironmental concerns) and advise the Chairman of the Board be an independent director. The Chief Executive Officer’s service as Chairman does not impair the Board’s independence. The changes in corporate governance rules and regulations effected by the Sarbanes-Oxley Act of 2002 and the NYSE listing requirements have increased the role of independent directors and added additional protections for investors. The Company’s corporate governance structure ensures that strong, independent directors will continue to effectively oversee the Company’s management and key issues related to strategy, risk and integrity. The Company has long been a leader in having a strong and independent Board. Ten of the 12 nominees for director are independent. Only independent directors serve on the Audit Committee, the Human Resources Committee and the Nominating and Corporate Governance Committee. In October 2002, non-management directors also initiated regular executive sessions. These sessions, currently scheduled for six times a year, take place after regular Board meetings outside the presence of the Chief Executive Officer or any other Company employee. The executive sessions are currently led by the Chairman of the Nominating and Corporate Governance Committee, acting as the Lead Director. The Lead Director is an independent director, selected by the Nominating and Corporate Governance Committee, with such selection ratified by the non-management members of the Board. The Lead Director convenes and chairs meetings of both the non-management directors and the independent directors in executive session; presides at all meetings of the Board at which the Chairman is not present; regularly polls the non-management directors for agenda items for meetings; serves as a liaison between the Chairman and Chief Executive Officer and the non-management directors; collaborates with the Chairman and Chief Executive Officer in developing the agenda for meetings of the Board and approves such agendas; approves information that is sent to the Board; collaborates with the Chairman and the Chief Executive Officer and the chairpersons of the standing committees in developing and managing the schedule of meetings of the Boardimplementing long-term strategies and approves such schedules; collaborates with the Chairman and Chief Executive Officer in developing the budget of the Board; and if requested by major shareholders, ensures that he or she is available for consultation and direct communication.

The Board believes that combining the offices of Chairman and Chief Executive Officer contributes to a more efficient and effective Board. The Chief Executive Officer bears primary responsibility for managing the Company’s business day to day. As such, the Board believes the Chief Executive Officer is the person in the best position to chair regular Board meetings and help ensure that key business issues and interests of all the Company’s stakeholders (shareholders, employees, communities and customers) are broughtplans relating to the Board’s attention. In addition, any director may requestCallaway Plant. Ameren’s Safety and Health Policy and Environmental Policy, together with Board oversight and regulation by the inclusion of specific agenda items for Board meetings.

There is no evidence that having one person serve as both Chairman ofNRC, will appropriately and adequately address the potential issues raised by this proposal. Accordingly, the Board of Directors and Chief Executive Officer has had a detrimental effect on Board or Company performance. Furthermore, in its supporting statement, the proponent refers to certain corporate scandals. The Company has not been a party to any such corporate scandals. The Board believes that the Company is currently well served by having one person serve as Chairman of the Board and Chief Executive Officer. The Company’s By-Laws give the Board the flexibility, based upon the Board’s determination of what is in the best interests of the Company and its shareholders, in light of then-current and anticipated future circumstances, to either separate the offices of Chairman and Chief Executive Officer or combine them. The proposal advocated by the proponent would require a particular structure and limit the Board’s flexibility to organize its functions and conduct its business in the manner it deems most advantageous to the Company.

Directors of the Company, including the Chairman, are bound by fiduciary obligations imposed by state law to serve the best interests of the shareholders. Separating the offices of Chairman and Chief Executive Officer would not serve to enhance or lessen the fiduciary duties of any director of the Company.

The Board believes that the interests of the Company and its shareholders are best served at this time through the experienced leadership and efficient operation afforded by a full-time Chairman and Chief Executive Officer, subject to oversight and review by the Company’s independent directors, and therefore the Board unanimously recommends voting AGAINST ITEM (4).4.

Passage of the proposal requires the affirmative vote of a majority of the votes cast.shares entitled to vote on the proposal and represented in person or by proxy at the meeting at which a quorum is present.

Item (5):     Other Matters

The Board of Directors does not know of any matter, other than the election of Directors, approval of the Ameren Corporation 2006 Omnibus Incentive Compensation Plan, ratification of the appointment of independent auditors, and the shareholder proposalsproposal set forth above, which may be presented to the meeting. However, if any other matters should properly come before the meeting, it is the intention of the persons named in the enclosed proxy to vote thereon in accordance with their best judgment.

SECURITY OWNERSHIP

Security Ownership of More Than 5%5 Percent Shareholders – The following table contains information with respect to the ownership of Ameren Common Stock by each person known to the Company who is the beneficial owner of more than five percent of the outstanding Common Stock.

Security Ownership of Management – The following table sets forth certain information known to the Company with respect to beneficial ownership of Ameren Common Stock as of February 1, 20052006 for (i) each director and nominee for director of the Company, (ii) the Company’s Chairman, Chief Executive Officer and President, and the four other most highly compensated executive officers of the Company (and/or its subsidiaries) who were serving as executive officers at the end of 2004,2005, named in the Summary Compensation Table below (the(collectively, the “Named Executive Officers”), and (iii) all executive officers, directors and nominees for director as a group.

The address of all persons listed above is c/o Ameren Corporation, 1901 Chouteau Avenue, St. Louis, Missouri 63103.

Stock Ownership Guideline for Officers –In October 2005, the Company’s Board of Directors adopted, effective January 1, 2006, a stock ownership guideline applicable to all of the officers of the Company and its subsidiaries. Under this guideline, within five years of its January 1, 2006 effective date or within five years after initial election as an officer, each officer is encouraged to own shares of the Company’s Common Stock valued as a percentage of base salary as follows: President and Chief Executive Officer (500 percent), Executive Vice President (400 percent), Senior Vice President (300 percent) and Vice President (200 percent). See “Director Compensation” under “Item 1: Election of Directors” above for a description of the stock ownership guideline applicable to the Company’s non-management directors.

Section 16(a) Beneficial Ownership Reporting Compliance – Section 16(a) of the Securities Exchange Act of 1934, as amended, requires the Company’s directors and executive officers and persons who own more than 10 percent of the Company’s Common Stock to file reports of their ownership in the equity securities of the Company and its subsidiaries and of changes in that ownership with the SEC and the NYSE. SEC regulations also require the Company to identify in this proxy statement any person subject to this requirement who failed to file any such report on a timely basis. Based solely on a review of the filed reports and written representations that no other reports are required, each of the Company’s directors and executive officers complied with all such filing requirements during 2004.2005. The Company does not have any greater than 10 percent shareholders.

EXECUTIVE COMPENSATION

Notwithstanding anything to the contrary set forth in any of the Company’s filings under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, that might incorporate other filings with the SEC, including this proxy statement, in whole or in part, the following Ameren Corporation Human Resources Committee Report on Executive Compensation and the Performance Graph on page 2532 shall not be deemed to be incorporated by reference into any such filings.

Ameren Corporation Human Resources Committee Report on Executive Compensation

The philosophy of the Human Resources Committee of Ameren Corporation’s Board of Directors for compensation of the executive officers of Ameren Corporation and its subsidiaries (collectively referred to in this Report as “Ameren”) is to provide a competitive total compensation program that is based on the approximatesize-adjusted median of the range of compensation paid by similar utility industry companies, adjusted for Ameren’s short- and long-term performance and the individual’s performance. The adjustment for Ameren’s performance aligns the interest of management with that of shareholders to maximize shareholder value. Accordingly, the Human Resources Committee, which is comprised entirely of independent Directors, makes annual reviews of the compensation paid to the executive officers of Ameren in order to (i) support Ameren’s overall business strategy and objectives; (ii) attract and retain key executives; (iii) link compensation with business objectives and Ameren’s performance; and (iv) provide competitive compensation opportunities. The Human Resources Committee retains an independent executive compensation consultant who provides market information on executive compensation. BecauseThe executive compensation consultant was engaged by and reports to the Human Resources Committee. In reviewing and approving compensation actions for Chief Executive Officer Rainwater and the other executive officers, the Human Resources Committee believesevaluated Ameren’s performance in linking the interests of management2005 versus financial and shareholders, Ameren’s Board of Directors included stock ownership requirements for Ameren’s executive officersnon-financial goals, as described in order for restricted stock granted under the Long-Term Incentive Plan described below to vest.this Report. The Human Resources Committee’s compensation decisions with respect to the five highest paid officers of Ameren are subject to approval by Ameren Corporation’s Board of Directors. Following the annual reviews, the Human Resources Committee authorizes appropriate changes to the three basic variable components of the executive compensation program, which are:

First, in evaluating and setting base salaries for executive officers, including the Chief Executive OfficersOfficer of Ameren, the Human Resources Committee considers: individual responsibilities, including changes which may have occurred since the prior review; individual performance in fulfilling responsibilities, including the degree of competence and initiative exhibited; relative contribution to the

results of operations; the impact of operating conditions; the effect of economic changes on salary structure; and comparisons with

compensation paid by similar utility industry companies. The Human Resources Committee has not found it practicable to, and has not attempted to assign relative weights to the specific factors considered in determining the Chief Executive Officer’s and other executive officers’ compensation. During 2004,2005, Mr. Gary L. Rainwater served as Chief Executive Officer of Ameren Corporation and its principal subsidiaries, Union Electric Company, Central Illinois Public Service Company, CILCORP Inc., Central Illinois Light Company and since its acquisition in September 2004, Illinois Power Company. With respect to setting Mr. Rainwater’s 2004The annual base salary,salaries of all the Human Resources Committee gave special consideration to his promotion to Chief Executive Officerofficers listed in the Summary Compensation Table of Ameren Corporation on January 1, 2004.this proxy statement were fixed for 2005 as disclosed in that Table.

The second component of the executive compensation program is a performance-based Executive Incentive Compensation Plan (the “Short-Term Incentive Plan”) established by the Ameren Corporation Board of Directors, which provides specific, direct relationships between corporate results and Short-Term Incentive Plan compensation. For 2004,2005, Ameren consolidated year-end earnings per share (EPS) target levels were set by the Human Resources Committee. There were three EPS performance levels established for 2004.2005. “Threshold” is the minimum EPS performance level that incentives or bonuses will be funded; “Target” is the goal or desired level of EPS performance; and “Maximum” is the highest level of incentive funding based on exceptional EPS performance. If EPS reaches at least the Threshold target level, the Human Resources Committee authorizes cash incentive payments with respect to the EPS performance level within prescribed ranges based on individual performance and degree of responsibility. If EPS fails to reach the Threshold target level, no payments are made. Under the Short-Term Incentive Plan it is expected thatfor 2005, the incentive paymentspayment to the Chief Executive OfficersOfficer of Ameren will rangecould have ranged from 0-90%0 to 127.5 percent of base salary. For 2004,2005, the actual cash incentive payment to Chief Executive Officer Rainwater was 78%123.25 percent of base salary. This reflects a level of achievement exceeding the Target but short of the Maximum level in 2005 EPS. The Summary Compensation Table lists the Short-Term Incentive Plan cash bonus awards for 2005 (which were paid in 2006) for each executive listed.

The third component of the 20042005 executive compensation program is the Long-Term Incentive Plan of 1998 (the “Long-Term Incentive Plan”), which also ties compensation to performance. The Long-Term Incentive Plan was approved by Ameren Corporation shareholders at its 1998 annual meeting and provides for the grant of options, restricted stock, performance awards, stock appreciation rights and other awards. The Human Resources Committee determines who participates in the Long-Term Incentive Plan and the number and types of awards to be made. It also sets the terms, conditions, performance requirements and limitations applicable to each award under the Long-Term Incentive Plan. Since 2001, awards have been exclusively in the form of restricted stock which has the potential to vest equally over a seven-year period from the date of grant (one-seventh(approximately one-seventh on each anniversary date) based upon the achievement of certain Ameren EPS performance levels (which correspond to the levels established for the Short-Term Incentive Plan) and prior to February 2006, upon the officer’s achievement of required stock ownership levels based on position and salary. There will be no annual vesting if the EPS performance does not reach a minimum level that is established annually over the seven-year vesting period. The vesting period is reduced from seven years to three years if Ameren’s EPS achieves a prescribed growth rate over the three-year period. In February 2006, the Human Resources Committee recommended and the Board of Directors approved the elimination of the stock ownership requirement as a condition to vesting in the restricted stock awards granted under the Long-Term Incentive Plan to facilitate the transition from that plan to the new 2006 Omnibus Incentive Compensation Plan currently proposed for shareholder approval. Executive officers cannot receive more than the original restricted stock grants plus dividend appreciation on shares granted under the Long-Term Incentive Plan. Under the Long-Term Incentive Plan, it is expected that the value of restricted stock awards to Ameren’s executive officers will range from 40% to 85% of base salary.

In 2004,2005, Chief Executive Officer Rainwater was granted a performance-based restricted stock award of 11,92313,279 shares of Ameren Common Stock valued at $552,512 (85%$680,018 (85 percent of Chief Executive Officer Rainwater’s 2005 base salary) based on the closing market price of $46.34$51.21 per share on

February 13, 2004,11, 2005, the date the restricted stock was awarded. The Summary Compensation Table lists the restricted stock awards made during 2005 for each executive listed based on performance for 2004.

Chief Executive Officer Rainwater’s proposed compensation is presented, reviewed and analyzed in the context of all of the components of his total compensation over the course of at least two meetings, generally beginning with the last Human Resources Committee meeting of the year preceding any base salary adjustment and award under either the Short-Term Incentive Plan or the Long-Term Incentive Plan and ending with the first meeting of the Human Resources Committee of the year in which any such adjustment or award is made. In the interim, members of the Human Resources Committee have time to ask for additional information and to raise and discuss further questions.

In determining the 20042005 compensation of Chief Executive Officer Rainwater, as well as compensation for the other executive officers, including salary, bonus, long-term incentive compensation, perquisites and other benefits, including potential payouts upon a change in control, the Human Resources Committee considered and applied the factors discussed above. Further, the reported compensation reflects a level of

achievement exceeding the Target but short of the Maximum level in 2004 EPS. Based upon its review of Ameren’s executive compensation program and the advice and guidance that the Human Resources Committee has received from its independent executive compensation consultant, the Human Resources Committee believes that the program’s basic structurelong-term incentive component of the Company’s executive compensation program was below the size-adjusted market median.

The Board of Directors, acting on the recommendation of the Human Resources Committee, unanimously approved a new incentive compensation plan with both short-term and long-term incentive components, subject to shareholder approval. This new plan, the 2006 Omnibus Incentive Compensation Plan, attached to this proxy statement as Appendix B and described in Item 2 of this proxy statement, will provide a basis for future equity compensation awards designed to be competitive with similar utility industry companies that are competitors for executive talent and to focus on both short- and long-term performance as measured by financial results and value creation for shareholders. Performance measures under the Plan are designed to support the Company’s business strategies. Beginning in 2006, the Human Resources Committee expects to make greater use of performance share units in delivering annual long-term awards. These awards also support the stock ownership guideline applicable to the Company’s officers. The ownership guideline for the Chief Executive Officer is appropriate, competitive and effectivefive times annual base salary; other officers have stock ownership guidelines ranging from two to serve the purposes for which it was established.four times annual base salary.

Human Resources Committee:

Gordon R. Lohman,Richard A. Liddy, Chairman

Thomas A. HaysGordon R. Lohman

Richard A. LiddyLumpkin

John Peters MacCarthyHarry Saligman

Patrick T. Stokes

Human Resources Committee Interlocks and Insider Participation

The current members of the Human Resources Committee of the Board of Directors, for the 2004 fiscal yearMessrs. Liddy, Lohman, Lumpkin, Saligman and Stokes, were Messrs. Lohman, Hays, Liddy and MacCarthy. No member of this committee wasnot at any time during the 2004 fiscal year2005 or at any other time an officer or employee of the Company, and no member had any relationship with the Company requiring disclosure under applicable SEC rules. No executive officer of the Company has served on the board of directors or compensation committee of any other entity that has or has had one or more executive officers who served as a member of the Company’s Board of Directors or the Human Resources Committee during the 2004 fiscal year.2005.

Performance Graph

ThisThe following graph shows Ameren’s (NYSE ticker symbol AEE) cumulative total shareholder return during the five fiscal years ended December 31, 2004.2005. The graph also shows the cumulative total returns of the S&P 500 Index and the Edison Electric Institute (“EEI”) Index. The comparison assumes $100 was invested on January 1, 20002001 in Ameren Common Stock and in each of the indices shown and assumes that all of the dividends were reinvested.

Note: Ameren management consistently cautions that the stock price performance shown in the graph above should not be considered indicative of potential future stock price performance.