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                                                                     EXHIBIT 5.1


                                 July 21, 1997


Neurocrine Biosciences, Inc.
3050 Science Park Road
San Diego, California 92121

         Re:  Registration Statement on Form S-8

Ladies and Gentlemen:

         We have examined the Registration Statement on Form S-8 to be filed by
you with the Securities and Exchange Commission on or about July 22, 1997 (the
"Registration Statement") in connection with the registration under the
Securities Act of 1933, as amended, for an aggregate of 800,000 shares of your
Common Stock under the Amended 1992 Incentive Stock Plan.  Such shares of
Common Stock are referred to herein as the "Shares", and such plan is referred
to herein as the "Plan".  As your counsel in connection with this transaction,
we have examined the proceedings taken and are familiar with the proceedings
proposed to be taken by you in connection with the issuance and sale of the
Shares pursuant to the Plan.

         It is our opinion that, when issued and sold in the manner described
in the Plan and pursuant to the agreements which accompany each grant under the
Plan, the Shares will be legally and validly issued, fully-paid and
non-assessable.

         We consent to the use of this opinion as an exhibit to the
Registration Statement, and further consent to the use of our name wherever
appearing in the Registration Statement and any amendments thereto.



                                           Very truly yours,

                                           WILSON, SONSINI, GOODRICH & ROSATI
                                           Professional Corporation



                                          /s/ Wilson, Sonsini, Goodrich & Rosati