NOV (NOV) 10-K 2007 FY Annual report

Exhibit 32.2

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350

In connection with the Annual Report of National Oilwell Varco, Inc. (the “Company”) on Form 10-K for the year ended December 31, 2007 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Clay C. Williams, Sr. Vice President and Chief Financial 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 my knowledge:

     (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.

Date: February 28, 2008	By:	/s/ Clay C. Williams
	Clay C. Williams
	Senior Vice President and Chief Financial Officer