Exhibit 5.1

                                LATHAM & WATKINS

                        12626 HIGH BLUFF DRIVE, SUITE 300

                           SAN DIEGO, CALIFORNIA 92130

                                 (858) 523-5400

July 16, 2001

Neurocrine Biosciences, Inc.
10555 Science Center Drive
San Diego, California 92121

Re:      Form S-8 Registration Statement

Ladies and Gentlemen:

     In connection  with the  registration  by Neurocrine  Biosciences,  Inc., a
Delaware  corporation  (the  "Company"),  and aggregate of of 850,000  shares of
common stock,  par value $0.001 per share (the  "Shares"),  of the Company to be
issued pursuant to the Neurocrine  Biosciences,  Inc. 1992 Incentive Stock Plan,
as amended,  and the Neurocrine  Biosciences,  Inc. 1996 Employee Stock Purchase
Plan, as amended  (collectively the "Plans"),  under the Securities Act of 1933,
as amended (the "Act"),  on a Registration  Statement on Form S-8 filed with the
Securities  and  Exchange  Commission  on July 16, 2001 (as amended from time to
time, the "Registration Statement"), you have requested our opinion with respect
to the matters set forth below.

     In our capacity as your counsel in connection  with such  registration,  we
are familiar with the proceedings  taken and proposed to be taken by the Company
in connection with the  authorization,  issuance and sale of the Shares, and for
the  purposes of this  opinion,  have assumed  such  proceedings  will be timely
completed in the manner presently proposed. In addition, we have made such legal
and factual examinations and inquiries, including an examination of originals or
copies certified or otherwise  identified to our satisfaction of such documents,
corporate  records and  instruments,  as we have deemed necessary or appropriate
for purposes of this opinion.

     In our examination,  we have assumed the genuineness of all signatures, the
authenticity of all documents  submitted to us as originals,  and the conformity
to authentic original documents of all documents submitted to us as copies.

     We are opining herein as to the effect on the subject  transaction  only of
the General Corporation Law of the State of Delaware,  and we express no opinion
with respect to the applicability  thereto,  or the effect thereon, of any other
laws,  or as to any  matters  of  municipal  law or the laws of any other  local
agencies within the state.

     Subject to the foregoing, it is our opinion that as of the date hereof, the
Shares have been duly authorized,  and, upon the issuance of and payment for the
Shares in accordance  with the terms set forth in the Plans,  the Shares will be
validly issued, fully paid and nonassessable.

     We consent to your  filing this  opinion as an exhibit to the  Registration
Statement.

                                          Very truly yours,

                                          /s/ LATHAM & WATKINS