EXHIBIT 99.1


                                 CONTACTS:           Mark Perry
                                                     Senior Vice President,
                                                     Chief Financial Officer
                                                     and General Counsel
                                                     650-522-5772

                                                     Susan Hubbard
                                                     Investor Relations
FOR IMMEDIATE RELEASE                                650-522-5715


                 GILEAD SCIENCES AMENDS STOCKHOLDER RIGHTS PLAN


FOSTER CITY, CA, OCTOBER 22, 1999 - Gilead Sciences, Inc. (Nasdaq: GILD) today
announced that its Board of Directors has approved an amendment to its
Stockholder Rights Plan, which was originally adopted in November 1994. The
amendment to the Rights Plan provides, among other things, for an increase in
the exercise price of the rights under the Rights Plan from $60 to $400 and an
extension of the term of the Rights Plan to October 20, 2009.

The Rights Plan is designed to enable all Gilead stockholders to realize the
full value of their investment and to provide for fair and equal treatment for
all stockholders in the event that an unsolicited attempt is made to acquire
Gilead. The amendment of the Rights Plan is not in response to any particular
proposal.

The rights will continue to trade with Gilead's Common Stock, unless and until
they are separated upon the occurrence of certain future events. Gilead's Board
of Directors may terminate the Rights Plan at any time or redeem the rights
prior to the time a person acquires more than 15% of Gilead's Common Stock. The
Gilead Board of Directors will also have the ability to redeem the rights under
limited circumstances following an acquisition of more than 15% of Gilead's
Common Stock. The amended Rights Plan will be filed with the Securities and
Exchange Commission in a Form 8-K

Gilead Sciences, headquartered in Foster City, CA, is an independent
biopharmaceutical company that seeks to provide accelerated solutions for
patients and the people who care for them. The Company discovers, develops,
manufactures and commercializes proprietary therapeutics for challenging
infectious diseases (viral, fungal and bacterial infections) and cancer. Gilead
maintains research, development or manufacturing facilities in Foster City, CA,
Boulder, CO, San Dimas, CA, and Cambridge, UK, and sales and marketing
organizations in the United States, Europe and Australia. For more information
about Gilead, visit the company's Web site at www.gilead.com.


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