EXHIBIT 5.1

                                 BRYAN CAVE LLP

                           1290 AVENUE OF THE AMERICAS
                            NEW YORK, NEW YORK 10104
                                 (212) 541-2000

                               September 24, 2002


Activision, Inc.
3100 Ocean Park Boulevard
Santa Monica, California 90405

Ladies and Gentlemen:

     We refer to the Registration Statement on Form S-8 (the "Registration
Statement") to be filed by Activision, Inc., a Delaware corporation (the
"Company"), on or about the date hereof with the Securities and Exchange
Commission (the "Commission") in connection with the registration under the
Securities Act of 1933, as amended (the "Securities Act"), of 2,350,000 shares
of the Company's common stock, $.000001 par value per share (the "Common
Stock"), reserved for issuance pursuant to the terms of the Company's 2002
Incentive Plan (the "Plan").

     We are familiar with the Amended and Restated Certificate of Incorporation,
as amended, and the Amended and Restated By-laws of the Company and have
examined copies of the Plan, the resolutions adopted by the Company's Board of
Directors, and originals or copies, certified or otherwise identified to our
satisfaction, of such other documents, evidence of corporate action,
certificates and other instruments, and have made such other investigations of
law and fact, as we have deemed necessary or appropriate for the purposes of
this opinion.

     Based upon the foregoing, it is our opinion that the 2,350,000 shares of
Common Stock reserved for issuance pursuant to the terms of the Plan have been
duly authorized and, when issued in accordance with the terms of the Plan and in
accordance with Awards that have been or may be granted under and in conformity
with the Plan ("Awards") and upon payment of the purchase price therefor, if
any, provided for any Common Stock issued pursuant to such Awards, will be
validly issued, fully paid and non-assessable.

     We hereby consent to the use of this opinion in the Registration Statement.
In giving this consent, we do not thereby admit that we come within the category
of persons whose consent is required under Section 7 of the Securities Act or
the Rules and Regulations of the Commission thereunder.

                                                Very truly yours,



                                                /s/ Bryan Cave LLP