GILEAD SCIENCES, INC.
1991 STOCK OPTION PLAN
ADOPTED NOVEMBER 15, 1991
AMENDED APRIL 8, 1992
AMENDED APRIL 21, 1993
AMENDED OCTOBER 17, 1995
AMENDED AND RESTATED JANUARY 22, 1998
AMENDED MARCH 30, 1999
TERMINATION DATE: OCTOBER 31, 2001
(a) The Plan initially was adopted on November 15, 1991 and amended through October 17, 1995 (the "Initial
Plan"). The Initial Plan hereby is amended and restated in its entirety effective as of January 22, 1998. The terms
of the Plan (excluding the amended provision relating to the exercise price of Nonstatutory Stock Options) shall
apply to all options granted pursuant to the Initial Plan.
(b) The purpose of the Plan is to provide a means by which selected Employees and Directors of, and
Consultants to, the Company and its Affiliates may be given an opportunity to purchase stock of the Company.
(c) The Company, by means of the Plan, seeks to retain the services of persons who are now Employees of or
Consultants to the Company, to secure and retain the services of new Employees and Consultants, and to
provide incentives for such persons to exert maximum efforts for the success of the Company.
(d) The Company intends that the Options issued under the Plan shall, in the discretion of the Board or any
Committee to which responsibility for administration of the Plan has been delegated pursuant to subsection 3(c),
be either Incentive Stock Options or Nonstatutory Stock Options. All Options shall be separately designated
Incentive Stock Options or Nonstatutory Stock Options at the time of grant, and in such form as issued pursuant
to Section 6, and a separate certificate or certificates will be issued for shares purchased on exercise of each type
(a) "AFFILIATE" means any parent corporation or subsidiary corporation of the Company, whether now or
hereafter existing, as those terms are defined in Sections 424(e) and (f) respectively, of the Code.
(b) "BOARD" means the Board of Directors of