Exhibit 32.2

Certification of Chief Executive Officer 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 Cepheid (the "Company") on Form 10-Q for the quarter ended September 30, 2003, as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, John R. Sluis, as Vice President of Finance and Chief Financial Officer of the Company, hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1) The Report fully complies with the requirements of Section 13(a) 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 results of operations of the Company.

Date: November 13, 2003

By:  /s/ John R. Sluis

John R. Sluis
Vice President of Finance and
Chief Financial Officer

This certification accompanies this report pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and shall not be deemed to be filed by the Company for purposes of Section 18 of the Securities Exchange Act of 1934.