Exhibit 99.1

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, Bernard Aronson, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Quarterly Report of Synplicity, Inc. on Form 10-Q for the quarter ended September 30, 2002 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in such Quarterly Report fairly presents in all material respects the financial condition and results of operations of Synplicity, Inc.

Date: November 8, 2002	By: /s/    Bernard Aronson
	Name: Bernard Aronson
	Title: Chief Executive Officer, President and Director

I, Douglas S. Miller, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Quarterly Report of Synplicity, Inc. on Form 10-Q for the quarter ended September 30, 2002 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in such Quarterly Report fairly presents in all material respects the financial condition and results of operations of Synplicity, Inc.

Date: November 8, 2002	By: /s/    Douglas S. Miller
	Name: Douglas S. Miller
	Title: Vice President of Finance and Chief Financial Officer