OSI Systems (OSIS) 10-Q 2005 Q1 Quarterly report

Exhibit 32.1

CERTIFICATION

Certification of Chief Executive Officer

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section 1350

In connection with the Quarterly Report of OSI Systems, Inc. (the “Company”) on Form 10-Q for the quarter ended September 30, 2004 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Deepak Chopra, 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:

1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, and

2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company at the dates and for the periods presented in this Report.

Date: November 9, 2004

/s/ Deepak Chopra

Deepak Chopra

Chief Executive Officer