Agreement - Gilead Sciences Inc. and Michael F. Bigham


                                      AGREEMENT


      This Agreement (this 'Agreement') is made and entered into by and between
Gilead Sciences, Inc., a Delaware corporation ('Gilead') and Michael F. Bigham
('Employee'), effective as of May 24, 1996.

      WHEREAS, Employee has tendered his resignation from all positions he
holds with Gilead, effective as set forth below, in order to accept a position
as President and Chief Executive Officer of another company; and

      WHEREAS, Gilead has accepted Employee's resignation, and wishes to
provide him with certain benefits in consideration of Employee's promises and
covenants as contained herein;

      NOW THEREFORE, in consideration of the mutual promises and covenants
contained herein, it is hereby agreed by and between the parties hereto as
follows:

      1. RESIGNATION. Employee hereby resigns from the position of Executive
Vice President for Operations and Chief Financial Officer and from all other
positions he holds with the Company, effective as of July 1, 1996.  Gilead
hereby accepts such resignation.  From the effective date of this Agreement
through July 1, 1996, Employee shall remain in his current position at his
current level of salary and benefits, subject to Gilead's policies and
procedures.  After July 1, 1996, the parties shall have no further obligations
to each other except as provided in this Agreement or in other written
agreements between Employee and Gilead.

      2. STOCK OPTIONS. Exhibit A attached hereto sets forth all of the Gilead
stock options held by Employee as of the date of this Agreement, identified as
Option A through Option G on Exhibit A (the 'Options').  Employee and Gilead
agree that the Options are hereby amended as follows, effective as of the date
of this Agreement:

      (a) All of the unvested shares remaining under Option A (currently 32,396
      shares) shall be accelerated and Option A shall become exercisable in
      full upon the granting of marketing approval for Vistide-Registered 
      Trademark-  (cidofovir injection) by the U.S. Food and Drug
      Administration, provided such approval occurs before May 1, 1997.

      (b) Options B and C are converted from incentive stock options to
      nonqualified stock options.

      (c) Vesting under all of the Options shall continue until July 1, 1996
      and shall thereafter terminate, except to the extent provided in (a)
      above with respect to Option A.

      (d) To the extent vested, all of the Options shall be exercisable at any
      time on or before May 1, 1998, in whole or in part, notwithstanding the
      termination of Employee's employment.

      3. LOAN. The Loan Agreement entered into between the Company and Employee
as of August 18, 1992 is hereby modified such that the $100,000 loan Employee
received thereunder shall be due and payable in full on the earlier of May 1,
1997 or the date on which Employee's new employer replaces such loan, without
interest if paid by such date, payable as otherwise provided in such Loan
Agreement.


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      4. RELEASE OF CLAIMS. Gilead and Employee each agree to release and
forever discharge the other party from any claims, disputes, damages, payments
or obligations of any kind arising out of or related to Employee's employment by
or resignation from Gilead, to the extent such claims, disputes, damages,
payments or obligations arise out of agreements, events or conduct occurring at
any time prior to the date of this Agreement.  Each party acknowledges that it
has read and understands Section 1542 of the Civil Code of the State of
California regarding general releases of unknown claims, and expressly waives
the benefits and rights created by such section with respect to the release
granted in this Agreement.  This release shall not apply to or affect any claims
that either party may have arising out of the obligations created by this
Agreement or other written agreements between Employee and Gilead.

      5. GENERAL PROVISIONS.

                 a.     GOVERNING  LAW.  This Agreement shall be governed in
all respects by the laws of the State of California as such laws are applied to
agreements between California residents entered into and performed entirely in
California.

                 b.     SUCCESSORS AND ASSIGNS.  Except as otherwise expressly
provided herein, the provisions hereof shall inure to the benefit of, and be
binding upon, the successors, assigns, heirs, executors and administrators of
the parties hereto.

                 c.     ENTIRE AGREEMENT.  This Agreement constitutes the full
and entire understanding and agreement between the parties with regard to the
subject matter hereof and neither party shall be liable or bound to the other
party in any manner by any representations, warranties, covenants and agreements
except as specifically set forth herein and therein.

                 d.     SEPARABILITY.  In case any provision of this Agreement
shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby.

                 e.     COUNTERPARTS.  This Agreement may be executed in any
number of counterparts, each of which shall be an original, but all of which
together shall constitute one instrument.


      IN WITNESS WHEREOF, the parties have duly authorized and caused this
Agreement to be executed as of the effective date first set forth above.



GILEAD SCIENCES, INC.                            EMPLOYEE



By
  -----------------------                        -------------------------
                                                 Michael F. Bigham


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