UNITED STATES SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 11-K/A

Amendment No. 1

x           Annual Report pursuant to Section 15(d) of the Securities Exchange Act of 1934

FOR THE YEAR ENDED DECEMBER 31, 2006

OR

o      Transition Report pursuant to Section 15(d) of the Securities Exchange Act of 1934

For the transition period from . . . . to . . . .

Commission file number 1-7627

FRONTIER REFINING & MARKETING INC. and SUBSIDIARIES

COLLECTIVELY BARGAINED EMPLOYEES

RETIREMENT SAVINGS PLAN

(Full title of the plan)

FRONTIER OIL CORPORATION

(Name of issuer of the securities)

10000 Memorial Drive, Suite 600

Houston, Texas  77024-3411

(Address of issuer’s principal executive offices)

EXPLANATORY NOTE

The purpose of this Amendment No. 1 to the Company’s Form 11-K, originally filed  with the Securities and Exchange Commission on June 27, 2007, is to correct a typographical error in the Consent of Deloitte & Touche LLP filed as Exhibit 23 thereto.  The Company is filing as Exhibit 23 to this Form 11-K/A the corrected Consent of Deloitte & Touche LLP.  Except for the amendment described herein, this Form 11-K/A does not modify or update the disclosures in, or exhibits to, the Form 11-K originally filed on June 27, 2007.

EXHIBIT INDEX

Exhibit

Number                      Description

23                          Consent of Deloitte & Touche LLP

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, Frontier Oil Corporation has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

FRONTIER REFINING & MARKETING INC. and SUBSIDIARIES COLLECTIVELY BARGAINED EMPLOYEES RETIREMENT SAVINGS PLAN
By:	/s/ Nancy J. Zupan
	Nancy J. Zupan
	Vice President - Controller (principal accounting officer)

Date: July 12, 2007