O’REILLY AUTOMOTIVE, INC. AND SUBSIDIARIES

Exhibit 32.1 – CEO Certification

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 Annual Report of O’Reilly Automotive, Inc. (the “Company”) on Form 10-K/A for the period ended December 31, 2007, 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:

(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

June 10, 2008

This certification is made solely for purposes of 18 U.S.C. Section 1350, and not for any other purpose.