EXHIBIT 10.2


                                PROMISSORY NOTE
                                ---------------

$_______                                                   Palo Alto, California
                                                                  March 14, 1997


          ___________, ("Obligor"), for value received, hereby promises to pay
to the order of Maxygen, Inc. or holder ("Payee"), in lawful money of the United
States at the address of Payee set forth below, the principal sum of
___________________________ Dollars ($_______), together with interest on the
unpaid principal at the compounded annual rate of 6.42%.  Interest shall be due
and payable on December 31 and June 30 of each year.  Unpaid principal together
with all accrued interest shall be due and payable on the earlier of (a) March
14, 2001, or (b) 30 days after the date of termination of Obligor's employment
by Payee.  This Note may be prepaid, in whole or in part, at any time without
premium or penalty.

          If any payment of principal or interest on this Note shall become due
on a Saturday, Sunday, or a public holiday under the laws of the State of
California, such payment shall be made on the next succeeding business day and
such extension of time shall be included in computing interest in connection
with such payment.

          This Note is issued by the Obligor pursuant to, and is subject to, the
terms and conditions of a Securities Purchase Agreement dated March 14, 1997
(the "Agreement"), between Obligor and Payee relating to the sale of Payee's
stock to the Obligor (the "Shares").

          Upon payment in full of all principal and interest payable hereunder,
this Note shall be surrendered to Obligor for cancellation.

          Obligor waives presentment, demand for performance, notice of
nonperformance, protest, notice of protest, and notice of dishonor.  No delay on
the part of Payee in exercising any right hereunder shall operate as a waiver of
such right under this Note.  This Note is being delivered in and shall be
construed in accordance with the laws of the State of California.

          In the event that Obligor fails to make payment on any date for
payment hereinabove specified of all principal and interest due hereunder on
such date, Obligor shall be deemed to be in default hereunder.  In the event of
such default, Payee may, at Payee's option and in Payee's sole discretion, five
days after giving notice of default to Obligor, accelerate the maturity of all
amounts due under this Note by giving notice of such acceleration.

          If the indebtedness represented by this Note or any part thereof is
collected at law or in equity or in bankruptcy, receivership or other judicial
proceedings or if this Note is placed in the hands of attorneys for collection
after default, Obligor agrees to pay, in addition to the principal and interest
payable hereon, reasonable attorneys' fees and costs incurred by Payee.

          Any notice or other communication (except payment) required or
permitted hereunder shall be in writing and shall be deemed to have been given
upon delivery if personally


delivered or upon deposit if deposited in the United States mail for mailing by
certified mail, postage prepaid, and addressed as follows:

          If to Payee:
                         Maxygen, Inc.
                         3410 Central Expressway
                         Santa Clara, California  95051
                         Attention:  President


          If to Obligor:
                         __________________
                         c/o Maxygen, Inc.
                         4001 Miranda Avenue
                         Palo Alto, CA 94304

          Any payment shall be deemed made upon receipt by Payee.  Payee or
Obligor may change their address for purposes of this paragraph by giving to the
other party notice in conformance with this paragraph of such new address.


                                             Obligor: ________________________

                                      -2-