Exhibit 5.1


INTERNAL REVENUE SERVICE                              DEPARTMENT OF THE TREASURY
P.O. BOX 2508
CINCINNATI, OH 45201

Date:    September 20, 2002         Employer Identification Number:
                                        41-0222640
                                    DLN:
                                        17007010129022
DONALDSON COMPANY INC.              Person to Contact:
9301 JAMES AVE S MAIL STA 430           MARK E. HEFFKE                 ID# 31654
BLOOMINGTON, MN 55431               Contact Telephone Number:
                                        (877) 829-5500
                                    Plan Name:
                                        DONALDSON CO INC RETIREMENT
                                        SAVINGS PLAN
                                    Plan Number:  007

Dear Applicant:

     We have made a favorable determination on the plan identified above based
on the information you have supplied. Please keep this letter, the application
forms submitted to request this letter and all correspondence with the Internal
Revenue Service regarding your application for a determination letter in your
permanent records. You must retain this information to preserve your reliance on
this letter.

     Continued qualification of the plan under its present form will depend on
its effect in operation. See section 1.401-1(b)(3) of the Income Tax
Regulations. We will review the status of the plan in operation periodically.

     The enclosed Publication 794 explains the significance and the scope of
this favorable determination letter based on the determination requests selected
on your application forms. Publication 794 describes the information that must
be retained to have reliance on this favorable determination letter. The
publication also provide examples of the effect of a plan's operation on its
qualified status and discusses the reporting requirements for qualified plans.
Please read Publication 794.

     This letter relates only to the status of your plan under the Internal
Revenue Code. It is not a determination regarding the effect of other federal or
local statutes.

     This determination is subject to your adoption of the proposed amendments
submitted in your letter dated September 11, 2002. The proposed amendments
should be adopted on or before the date prescribed by the regulations under Code
section 401(b).

     This determination letter is applicable for the amendment(s) executed on
September 6, 2000.

     This determination letter is also applicable for the amendment(s) dated on
December 27, 2000.

     This letter considers the changes in qualification requirements made by the
Uruguay Round Agreements Act, Pub. L. 103-465, the Small Business Job Protection
Act of 1996, Pub. L. 104-188, the Uniformed Services Employment and Reemployment
Rights Act of 1994, Pub. L. 103-353, the Taxpayer Relief Act of 1997, Pub. L.
105-34, the Internal Revenue Service Restructuring and Reform Act of 1998, Pub.
L. 105-206, and the Community Renewal Tax Relief Act of 2000, Pub. L. 106-554.


                                                              Letter 835 (DO/CG)



                                      -2-

DONALDSON COMPANY INC


     This letter may not be relied on with respect to whether the plan satisfies
the requirements of section 401(a) of the Code, as amended by the Economic
Growth and Tax Relief Reconciliation Act of 2001, Pub L. 107-16.

     The requirement for employee benefits plans to file summary plan
descriptions (SPD) with the U.S. Department of Labor was eliminated effective
August 5, 1997. For more details, call 1-800-998-7542 for a free copy of the SPD
card.

     We have sent a copy of this letter to your representative as indicated in
the power of attorney.

     If you have questions concerning this matter, please contact the person
whose name and telephone number are shown above.


                                             Sincerely yours,


                                             /s/ Paul T. Shultz
                                             -----------------------------------

                                             Paul T. Shultz
                                             Director,
                                             Employee Plans Rulings & Agreements




Enclosures:
Publication 794


                                                              Letter 835 (DO/CG)