NightHawk Radiology 10-Q 2007 Q2 Quarterly report

Exhibit 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER

PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

I, Paul E. Berger, M.D., certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Quarterly Report on Form 10-Q of NightHawk Radiology Holdings, Inc. for the quarter ended June 30, 2007 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in such Quarterly Report on Form 10-Q fairly presents in all material respects the financial condition and results of operations of NightHawk Radiology Holdings, Inc.

Dated: July 31, 2007	By:	/s/ PAUL E. BERGER, M.D.
	Name:	Paul E. Berger, M.D.
	Title:	Chief Executive Officer (Principal Executive Officer)