EXHIBIT 99.1



                                  Certification
         Pursuant  to  Section  906  of  the   Sarbanes-Oxley   Act  of  2002
(Subsections (a) and (b) of Section 1350,  Chapter 63 of Title 18, United States
Code)

         Pursuant to section 906 of the  Sarbanes-Oxley Act of 2002 (subsections
(a) and (b) of section 1350,  chapter 63 of title 18, United States Code),  each
of the  undersigned  officers of  Synopsys,  Inc., a Delaware  corporation  (the
"Company"), does hereby certify, to such officer's knowledge, that:

         The  Quarterly  Report on Form 10-Q for the fiscal  quarter ended April
30,  2003 (the  "Form  10-Q") of the  Company  to which  this  Certification  is
attached as Exhibit 99.1 fully complies with the  requirements  of section 13(a)
or 15(d) of the Securities Exchange Act of 1934 and information contained in the
Form 10-Q fairly presents, in all material respects, the financial condition and
results of operations of the Company.

Dated: June 13, 2003


/s/ AART J. DE GEUS
Aart J. de Geus
Chief Executive Officer

Dated: June 13, 2003


/s/ STEVEN K. SHEVICK
Steven K. Shevick
Chief Financial Officer

The foregoing certification is being furnished solely pursuant to section 906 of
the Sarbanes-Oxley Act of 2002 (subsections (a) and (b) of section 1350, chapter
63 of title 18, United States Code) and is not deemed filed with the  Securities
and  Exchange  Commission  as part of the Form 10-Q or as a separate  disclosure
document and is not to be incorporated by reference into any filing of Synopsys,
Inc. under the Securities  Act of 1933, as amended,  or the Securities  Exchange
Act of 1934,  as  amended  (whether  made  before  or after the date of the Form
10-Q),  irrespective  of any general  incorporation  language  contained in such
filing.

A signed  original of this  written  statement  required by Section 906 has been
provided to Synopsys,  Inc. and will be retained by Synopsys, Inc. and furnished
to the Securities and Exchange Commission or its staff upon request.