EXHIBIT 32.01

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

     In connection with the Quarterly Report of PDF Solutions, Inc. (the “Company”) on Form 10-Q for the quarter ended March 31, 2006 as filed with the Securities and Exchange Commission on May 10, 2006 (the “Report”), I, John K. Kibarian, President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge:

     (1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

     (2) The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

/s/ JOHN K. KIBARIAN

John K. Kibarian

President and Chief Executive Officer

(Principal Executive Officer)

Date: May 10, 2006