Exhibit 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER
PURSUANT TO  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

I, Robert N. Stephens, certify to the best of my knowledge based upon a review of the Quarterly Report on Form 10-Q of Adaptec, Inc. for the period ended September 30, 2003 that (the “Form 10-Q”), the Form 10-Q fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934, as amended, and that information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of Adaptec, Inc. for the quarterly periods covered by the Form 10-Q.

	By: /s/ ROBERT N. STEPHENS
Date: October 31, 2003	Robert N. Stephens Chief Executive Officer

I, Marshall L. Mohr, certify to the best of my knowledge based upon a review of the Form 10-Q, that the Form 10-Q fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934, as amended, and that information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of Adaptec, Inc. for the periods covered by the Form 10-Q.

	By: /s/ MARSHALL L. MOHR
Date: October 31, 2003	Marshall L. Mohr Chief Financial Officer