EXHIBIT 32.1

CERTIFICATIONS

CERTIFICATION OF CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER
PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

I, Kenneth P. Wilcox, certify that, to my knowledge, the Quarterly Report of Silicon Valley Bancshares on Form 10-Q for the quarterly period ended September 30, 2003, (i) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and (ii) that the information contained in such Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of Silicon Valley Bancshares.

Date: November 14, 2003	/s/ Kenneth P. Wilcox
	Kenneth P. Wilcox
	President and Chief Executive Officer
	(Principal Executive Officer)

I, Marc Verissimo, certify that, to my knowledge, the Quarterly Report of Silicon Valley Bancshares on Form 10-Q for the quarterly period ended September 30, 2003, (i) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and (ii) that the information contained in such Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of Silicon Valley Bancshares.

Date: November 14, 2003	/s/ Marc Verissimo
	Marc Verissimo
	Chief Financial Officer
	(Principal Financial Officer)