O'Reilly Automotive (ORLY) 10-K 2009 FY Annual report

Exhibit 32.1 – CEO Certification

O’REILLY AUTOMOTIVE, INC. AND SUBSIDIARIES

O’REILLY AUTOMOTIVE, INC.

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 of O’Reilly Automotive, Inc. (the “Company”) on Form 10-K for the period ended December 31, 2009, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Greg Henslee, 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 result of operations of the Company.

/s/ Greg Henslee

Greg Henslee

Chief Executive Officer

February 26, 2010

This certification is made solely for purposes of 18 U.S.C. Section 1350, and not for any other purpose. This certification accompanies the Report pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and shall not, except to the extent required by the Sarbanes-Oxley Act of 2002, be deemed filed by the Company for purposes of Section 18 of the Securities Exchange Act of 1934, as amended.

A signed original of this written statement required by Section 906 of the Sarbanes-Oxley Act of 2002 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.