QuickLinks -- Click here to rapidly navigate through this document


PROSPECTUS SUPPLEMENT NO. 10 to Prospectus Dated January 15, 2003
of
COMPUTER ASSOCIATES INTERNATIONAL, INC.
Relating to
Resales by Selling Securityholders
of
5% Convertible Senior Notes
and Shares of Common Stock Issuable upon Conversion of the Senior Notes

        This Prospectus Supplement supplements the Prospectus dated January 15, 2003 (the "Prospectus"). This Prospectus Supplement should be read in conjunction with the Prospectus, which is to be delivered by selling securityholders to prospective purchasers along with this Prospectus Supplement. The information in the following table supersedes in part and supplements the information in the relevant section in the Prospectus.

Selling Holder

  Aggregate Principal
Amount of Notes
Beneficially
Owned and Offered

  Shares of
Common
Stock
Beneficially Owned

  Shares of
Common
Stock
Offered

  Shares of
Common
Stock
Stock Beneficially
Owned
After Completion
of the Offering

Arbitex Master Fund L.P. (1)   7,500,000   2,790,305   308,134   2,482,171

McMahan Securities Co. L.P. (2)

 

25,000

 

1,027

 

1,027

 

0

Merrill Lynch Pierce Fenner &
Smith Inc. (3)

 

7,172,000

 

295,931

 

294,658

 

1,273

Sagamore Hill Hub Fund Ltd. (4)

 

1,159,000

 

51,417

 

47,617

 

3,800

(1)
Clark K. Hunt, Jonathan P. Bren and Kenneth Tananbaum exercise voting and investment control over any shares of Common Stock issuable upon conversion of the Notes owned by this selling holder.

(2)
Norman L. Ziegler, Chief Financial Officer, exercises voting and investment control over any shares of Common Stock issuable upon conversion of the Notes owned by this selling holder.

(3)
Nate Boroff exercises voting and investment control over any shares of Common Stock issuable upon conversion of the Notes owned by this selling holder.

(4)
S. Scott Roth, Partner/Managing Director, exercises voting and investment control over any shares of Common Stock issuable upon conversion of the Notes owned by this selling holder.


Prospectus Supplement dated October 14, 2003




QuickLinks

PROSPECTUS SUPPLEMENT NO. 10 to Prospectus Dated January 15, 2003 of COMPUTER ASSOCIATES INTERNATIONAL, INC. Relating to Resales by Selling Securityholders of 5% Convertible Senior Notes and Shares of Common Stock Issuable upon Conversion of the Senior Notes