Form 8-A/A

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                 Amendment No. 3

                For Registration of Certain Classes of Securities
                     Pursuant to Section 12(b) or (g) of the
                         Securities Exchange Act of 1934


                          AGOURON PHARMACEUTICALS, INC.
             (Exact name of registrant as specified in its charter)


California                                                    33-0061928
(State of incorporation                                       (IRS Employer
or organization)                                        Identification No.)

                          10350 North Torrey Pines Road
                           La Jolla, California 92037
                    (Address of principal executive offices)

Securities to be registered pursuant to Section 12(b) of the Act:

Title of each class                               Name of each exchange on which
to be so registered                               each class is to be registered

         None                                                          N/A

If this Form relates to the  registration  of a class of securities  pursuant to
Section  12(b) of the  Exchange  Act and is  effective  upon filing  pursuant to
General Instruction A.(c), please check the following box. / /

If this Form relates to the  registration  of a class of securities  pursuant to
Section  12(g)  of  the  Exchange  Act  and is  effective  pursuant  to  General
Instruction A.(d), please check the following box. / /

Securities Act registration statement file number to which this form relates

Securities to be registered pursuant to Section 12(g) of the Act:

Preferred Stock Purchase Rights (the "Rights")





         The Registrant  hereby amends the following  items of its  Registration
Statement on Form 8-A dated November 7, 1996, as follows:

Item 1.           Description of Registrant's Securities to be Registered.

                  Pursuant  to  action  of the  Board of  Directors  of  Agouron
Pharmaceuticals,  Inc. (the "Company")  effective  November 10, 1998, the Rights
Agreement  attached  to the Form 8-A  filed  with the  Securities  and  Exchange
Commission on November 8, 1996, as thereafter amended,  was amended and restated
to, among other things,  (i) change the definition of "Acquiring Person" to mean
any person who becomes a beneficial owner of common shares  representing  twenty
percent (20%) or more of the common shares then  outstanding;  and (ii) effect a
two-for-one split of the rights with a corresponding  adjustment of the purchase
price therefor (reflecting a two-for-one split of the Company's common shares in
August  1997),  all as  more  fully  set  forth  (together  with  certain  other
modifications)  in the form of Amended and Restated  Rights  Agreement  attached
hereto as Exhibit 1.

Item 2.                                     Exhibits.

1.       Amended and Restated Rights Agreement dated as of November 10, 1998,
         between Agouron Pharmaceuticals, Inc. and ChaseMellon
         Shareholder Services, L.L.C.

                                    SIGNATURE

                  Pursuant to the  requirements  of Section 12 of the Securities
Exchange Act of 1934, as amended,  the Registrant has duly caused this Amendment
No. 3 to be signed on its behalf by the undersigned, thereto duly authorized.

                  Dated:  January 19, 1999.

                          AGOURON PHARMACEUTICALS, INC.

                          By:      /s/ PETER JOHNSON         
                                   Peter Johnson
                                   President and
                                   Chief Executive Officer






                                  EXHIBIT INDEX

Exhibit

1.       Amended and Restated Rights Agreement dated as of November 10, 1998,
         between Agouron Pharmaceuticals, Inc. and ChaseMellon
         Shareholder Services, L.L.C.