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                                EXHIBIT 99-A(1)
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                                GENENTECH, INC.
 
                            1991 EMPLOYEE STOCK PLAN
                (AS AMENDED AND RESTATED AS OF OCTOBER 25, 1995)
 
     1. Purpose
 
     The purpose of this 1991 Employee Stock Plan (the "Plan") is to provide
employees of Genentech, Inc. (the "Company"), and its U.S. subsidiaries
designated by the Company's Board of Directors, who wish to become stockholders
of the Company an opportunity to purchase (i) shares of Callable Putable Common
Stock of the Company, or (ii) shares of Common Stock of the Company, to the
extent shares of Callable Putable Common Stock are converted to Common Stock in
accordance with the Company's Certificate of Incorporation (the shares referred
to in clauses (i) and (ii) above being hereinafter referred to collectively as
the "Shares"). The Plan is intended to qualify as an "employee stock purchase
plan" within the meaning of Section 423 of the Internal Revenue Code of 1986, as
amended (the "Code").
 
     2. Eligible Employees
 
     Subject to the provisions of Sections 7, 8 and 9 below, any individual who
is in the full-time employment of the Company on the day on which a Grant Date
(as defined in Section 3 below) occurs is eligible to participate in an offering
of Shares made by the Company hereunder. In addition, the Board of Directors may
at any time designate one or more of the Company's U.S. subsidiary corporations
(as defined in Section 425(f) of the Code) to be included in an offering of
Shares under the Plan. Full-time employment shall mean employment by the Company
or its designated U.S. subsidiary for:
 
          (a) 20 hours or more per week; and
 
          (b) more than five months in the calendar year.
 
     3. Grant Dates
 
     From time to time, the Board of Directors may fix a date (a "Grant Date")
or a series of dates (each of which is a "Grant Date") on which the Company will
grant rights to purchase Shares ("Rights") to employees eligible to participate.
 
     4. Prices
 
     The purchase price per Share for Shares covered by a grant of Rights
hereunder shall be determined by the Board of Directors, but in no event shall
be less than the lesser of:
 
          (a) eighty-five percent (85%) of the fair market value of a Share on
     the Grant Date on which such Right was granted; or
 
          (b) eighty-five percent (85%) of the fair market value of a Share on
     the date such Right is exercised as to that Share.
 
     5. Exercise of Rights and Method of Payment
 
          (a) Rights granted under the Plan will be exercisable on specific
     dates as determined by the Board of Directors.
 
          (b) The method of payment for Shares purchased upon exercise of Rights
     granted hereunder shall be through regular payroll deductions or by lump
     sum cash payment, or both, as determined by the Board of Directors. No
     interest shall be paid upon payroll deductions or other payments in
     exercise of Rights unless specifically provided for by the Board of
     Directors.
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     6. Terms of Rights
 
     Rights granted hereunder shall be exercisable during a twenty-seven (27)
month period or such shorter period as determined by the Board of Directors. All
Rights granted to an employee shall terminate upon termination of full-time
employment of the employee. Any payments received by the Company from a
participating employee with respect to a Right granted hereunder and not
utilized for the purchase of Shares upon exercise of such Right shall be
promptly returned to such employee by the Company after termination of such
Right, except that amounts that were not so utilized because such amounts were
insufficient to purchase a whole Share may be applied toward the purchase of
Shares pursuant to a Right subsequently granted hereunder, if any.
 
     7. Shares Subject to the Plan
 
     No more than three million eight hundred thousand (3,800,000) Shares may be
sold pursuant to Rights granted under the Plan. Appropriate adjustments in the
above figure, in the number of Shares covered by outstanding Rights granted
hereunder, in the exercise price of the Rights and in the maximum number of
Shares which an employee may purchase (pursuant to Section 9 below) shall be
made to give effect to any mergers, consolidations, reorganizations,
recapitalizations, stock splits, stock dividends or other relevant changes in
the capitalization of the Company occurring after the effective date of the
Plan, provide that no fractional Shares shall be subject to a Right and each
Right shall be adjusted downward to the nearest full Share. Any agreement of
merger or consolidation will include provisions for protection of the then
existing Rights of participating employees under the Plan. Either authorized and
unissued Shares or issued Shares heretofore or hereafter reacquired by the
Company may be made subject to Rights under the Plan. If for any reason any
Right under the Plan terminates in whole or in part, Shares subject to such
terminated Right may again be subject to a Right under the Plan.
 
     8. Limitations on Grants
 
     Anything to the contrary notwithstanding, pursuant to Section 423 of the
Code:
 
          (a) No employee shall be granted a Right hereunder if such employee,
     immediately after the Right is granted, owns stock possessing five percent
     (5%) or more of the total combined voting power or value of all classes of
     stock of the Company, its parent corporation (as defined in Section 425(c)
     of the Code) or any subsidiary corporation, in each case computed in
     accordance with Section 423(b)(3) of the Code.
 
          (b) No employee shall be granted a Right which permits his Rights to
     purchase Shares under all employee stock purchase plans of the Company and
     its subsidiaries to accrue at a rate which exceeds twenty-five thousand
     dollars ($25,000) (or such other maximum as may be prescribed from time to
     time by the Code) of fair market value of such Shares (determined at the
     time such Right is granted) for each calendar year in which such Right is
     outstanding at any time, all in accordance with the provisions of Section
     423(b)(8) of the Code.
 
     9. Limits on Participation
 
     (a) Participation shall be limited to eligible employees who enroll under
the Plan.
 
     (b) No Right granted to any participating employee shall cover more than
twelve thousand (12,000) Shares.
 
     (c) No more than One Hundred Eighty Thousand (180,000) Shares may be
purchased during any calendar quarter upon the exercise of Rights granted under
the Plan; provided, however, that for those calendar quarters in which the
Company pays regular annual bonuses to eligible employees, the maximum aggregate
numbers of Shares which may be purchased upon the exercise of Rights shall be
Two Hundred Thousand (200,000) Shares. If the aggregate purchases of Shares upon
exercises of Rights granted under the Plan would exceed the applicable maximum
number for a particular calendar quarter, the maximum permitted number of Shares
shall be allocated to the exercising participants in proportion to the number of
Shares they would otherwise purchase during such calendar quarter.
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     10.  Employee's Rights as Stockholder
 
     No participating employee shall have any Rights as a stockholder in the
Shares covered by a Right granted hereunder until such Right has been exercised,
full payment has been made for the corresponding Shares and the purchase has
been entered in the records of the Transfer Agent for the Shares.
 
     11.  Rights Not Transferable
 
     Rights under the Plan are not assignable or transferable by a participating
employee.
 
     12.  Amendments or Discontinuance of the Plan
 
     The Board of Directors of the Company shall have the right to amend, modify
or terminate the Plan at any time without notice; provided, however, that the
then existing Rights of all participating employees shall not be adversely
affected thereby, except that in the case of a participating employee of a
foreign branch of the Company or a designated U.S. subsidiary corporation the
Plan may be varied to conform with local laws, and provided further that,
subject to the provisions of Section 7 above, no such amendment to the Plan
shall, without the approval of the stockholders of the Company:
 
          (a) Increase the total number of Shares which may be offered under the
     Plan;
 
          (b) Amend the Plan in any manner which would render Rights granted
     hereunder unqualified for special tax treatment under Section 421 of the
     Code.
 
     13.  Effective Date and Approvals
 
     The Plan shall become effective as of January 1, 1991. The Company's
obligation to offer, sell or deliver its Shares under the Plan is subject to the
approval of the Company's stockholders and any governmental approval required in
connection with the authorized issuance or sale of such Shares and is further
subject to the determination by the Company that all applicable securities laws
have been complied with.
 
     14.  Administration of the Plan
 
     The Board of Directors or any committee or person(s) to whom it delegates
its authority (the "Administrator") shall administer, interpret and apply all
provisions of the Plan. The Administrator may waive such provisions of the Plan
as it deems necessary to meet special circumstances not anticipated or covered
expressly by the Plan. Nothing contained in this Section shall be deemed to
authorize the Administrator to alter or administer the provisions of the Plan in
a manner inconsistent with the provisions of Section 423 of the Code.