Form 8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 31, 2006

FRONTIER OIL CORPORATION

(Exact name of registrant as specified in its charter)

Wyoming	1-7627	74-1895085
(State or other jurisdiction of incorporation or organization)	(Commission File Number)	(I.R.S. Employer Identification No.)

10000 Memorial Drive, Suite 600 Houston, Texas		77024-3411
(Address of principal executive offices)		(Zip Code)


Registrant's telephone number, including area code: (713) 688-9600

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 7.01.

Regulation FD Disclosure

On April 4, 2006, Frontier Oil Corporation (“Frontier”) announced that its wholly owned subsidiary, Frontier Oil and Refining Company, entered into a definitive agreement with Rocky Mountain Pipeline System LLC (“Rocky Mountain”) to support construction of a new crude pipeline from Guernsey, Wyoming to Rocky Mountain’s Fort Laramie, Wyoming tank farm and then to Frontier’s Cheyenne, Wyoming refinery.

A copy of the press release, dated April 4, 2006, is furnished as Exhibit 99.1 to this Form 8-K pursuant to Regulation FD. Accordingly, the information in Item 7.01 of this report will not be incorporated by reference into any registration statement filed by Frontier under the Securities Act of 1933, unless specifically identified therein as being incorporated therein by reference.

Item 9.01.

Financial Statements and Exhibits

Exhibit Number	Description
99.1	Frontier’s press release dated April 4, 2006.

SIGNATURES

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

	FRONTIER OIL CORPORATION


	By: /s/ Michael C. Jennings
	Michael C. Jennings
	Executive Vice President - Chief Financial Officer

Date: April 6, 2006