Iris International (IRIS) 10-Q 2005 Q2 Quarterly report

Exhibit 32.1

CERTIFICATION OF PRINCIPAL EXECUTIVE OFFICER

PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with Quarterly Report of IRIS International, Inc. (the “Company”) on Form 10-Q for the period ending June 30, 2005 as filed with the Securities and Exchange Commission on the date thereof (the “Report”), I, Cesar M. Garcia, 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 the best of 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 results of operations of the Company.

Dated: August 12, 2005

/s/ CESAR M. GARCIA

Cesar M. Garcia

Chief Executive Officer

This certification shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, or the Exchange Act, or otherwise subject to the liability of Section 18 of the Exchange Ace. Such certification shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Exchange Act, except to the extent that the Company specifically incorporates it by reference.