Entegris (ENTG) 10-Q 2007 Q2 Quarterly report

EXHIBIT 32.1

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 Report on Form 10-Q (the “Report”) of Entegris, Inc, a Minnesota corporation (the “Company”), for the period ended June 30, 2007 as filed with the Securities and Exchange Commission on the date hereof, I, Gideon Argov, President and Chief Executive 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) 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 results of operations of the Company.

Date: August 3, 2007

/s/ Gideon Argov

Gideon Argov

Chief Executive Officer