FIRST AMENDMENT TO GUARANTY


          This Amendment, dated as of October 8, 1992, is entered
into by FRONTIER OIL CORPORATION, a Delaware corporation (the
"Guarantor"), the banks (the "Banks") parties to the Credit
Agreement (as hereinafter defined) and UNION BANK, a California
banking corporation, as agent (the "Agent") for the Banks.

                            Recitals

     A.   The Banks and the Agent have entered into a Revolving
Credit and Letter of Credit Agreement dated as of August 10, 1992
(said Agreement, as it may hereafter be amended or otherwise
modified from time to time, herein called the "Credit Agreement")
with Frontier Oil and Refining Company, a Delaware corporation
(the "Borrower").  Terms defined in the Credit Agreement and not
otherwise defined herein have the same respective meanings when
used herein, and the rules of interpretation set forth in
Sections 1.2 and 1.3 of the Credit Agreement are incorporated by
reference herein.

     B.  The Guarantor, as the legal and beneficial owner of all
of the outstanding capital stock of the Borrower, has executed a
Guaranty dated as of August 18, 1992 (said Guaranty, as it may
hereafter be amended or otherwise modified from time to time,
herein called the "Guaranty") in favor of the Banks and the
Agent, guaranteeing all of the obligations of the Borrower under
the Credit Agreement and the other Credit Documents.

     C.   The Banks, the Agent and Guarantor wish to amend the
Guaranty to require written consent of all of the Banks in order
for waivers of certain covenants of the Guarantor set forth in
the Guaranty to be effective.

          Section 1.  Amendment to Guaranty.  Effective as of the
date hereof and subject to satisfaction of the conditions
precedent set forth in Section 2, the first sentence of Section 7
of the Guaranty is amended in full to read as follows:

          "Section 7.  Covenants.  The Guarantor covenants and
agrees that, so long as any part of the Guaranteed Obligations
remains unpaid, any Bank has any Commitment or any Letter of
Credit remains outstanding, the Guarantor will, unless the
Majority Banks (or, with respect to Sections 7.2(a) and (b) only,
all of the Banks) otherwise consent in writing, comply with all
of the covenants set forth below."

          Section 2.  Conditions to Effectiveness.  This
Amendment shall be become effective as of the date first written
above when all of the parties hereto have executed this Amendment
and the Borrower, Wainoco, FHI, FRI, FPLI and FPI have consented
to this Amendment.

          Section 3.  Representations and Warranties of
Guarantor.  The Guarantor represents and warrants as follows:

               (a)  The Guarantor is a corporation duly
organized, validly existing and in good standing under the laws
of the State of Delaware.

               (b)  The execution, delivery and performance by
the Guarantor of this Amendment and the Credit Documents, as
amended hereby, to which it is or is to be a party are within the
Guarantor's corporate powers, have been duly authorized by all
necessary corporate action and do not (i) contravene the
Guarantor's charter documents or bylaws, (ii) contravene any
Governmental Rule or contractual restriction binding on or
affective the Guarantor or (iii) result in or require the
creation or imposition of any Lien or preferential arrangement of
any nature (other than any created by the Credit Documents) upon
or with respect to any of the properties now owned or hereafter
acquired by the Guarantor.

               (c)  No Governmental Action is required for the
due execution, delivery and performance by the Guarantor of this
Amendment or any of the Credit Documents, as amended hereby, to
which the Guarantor is or is to be a party.

               (d)  This Amendment and each of the other Credit
Documents, as amended hereby, to which the Guarantor is a party
constitute legal, valid and binding obligations of the Guarantor
enforceable against the Guarantor in accordance with their
respective terms.

               (e)  The Stock Pledge Agreement constitutes a
valid and perfected a first-priority Lien on the Collateral
covered thereby, enforceable against all third parties in all
jurisdictions, and secures the payment of all obligations of the
Guarantor under the Guaranty, as amended hereby; and the
execution, delivery and performance of this Amendment do not
adversely affect the Lien of the Stock Pledge Agreement.

               (f)  The consolidated balance sheet of the
Guarantor and its Subsidiaries as of August 31, 1992 and the
related consolidated statements of income and cash flows from
operations of the Guarantor and its Subsidiaries for the month
then ended, certified by the chief financial officer or chief
accounting officer of the Guarantor as being true and correct and
copies of which have been furnished to the Banks, fairly present
the consolidated financial condition of the Guarantor and its
Subsidiaries as of such date and the consolidated results of the
operations of the Guarantor and its Subsidiaries for the month
ended on such date, all in accordance with generally accepted
accounting principles applied on a consistent basis.  Since
August 31, 1992 there has been no material adverse change in the
business, condition (financial or otherwise), operations,
performance, properties or prospects of the Guarantor or any of
its Subsidiaries.  The Guarantor and its Subsidiaries have no
material contingent liabilities except as disclosed in such
consolidated balance sheet or the notes thereto.

               (g)  There is no pending or, to the knowledge of
the Guarantor, threatened action or proceeding affecting the
Guarantor or any its Subsidiaries before any Governmental Person
or arbitrator that may materially and adversely affect the
financial condition or operations of the Guarantor or any of its
Subsidiaries or that purports to affect the legality, validity or
enforceability of this Amendment or any of the other Credit
Documents, as amended hereby, to which the Guarantor is a party.

          Section 4.  Reference to and Effect on Credit
Documents.

               (a)  On and after the effective date of this
Amendment, each reference in the Guaranty to "this Guaranty,"
"hereunder," "hereof" or any other expression of like import
referring to the Guaranty, and each reference in the other Credit
Documents to "the Guaranty," "thereunder," "thereof" or any other
expression of like import referring to the Guaranty, shall mean
and be a reference to the Guaranty as amended by this Amendment.

               (b)  Except as specifically amended above, the
Guaranty and the other Credit Documents shall remain in full
force and effect and are hereby ratified and confirmed.  Without
limiting the generality of the foregoing, the Stock Pledge
Agreement and all of the Collateral described therein do and
shall continue to secure the payment of all obligations of the
Guarantor under the Guaranty, as amended hereby.

               (c)  The execution, delivery and effectiveness of
this Amendment shall not, except as expressly provided herein,
operate as a waiver of any right, power or remedy of any Bank or
the Agent under any of the Credit Documents or constitute a
waiver of any provision of any of the Credit Documents.

          Section 5.  Costs, Expenses and Taxes.  The Guarantor
agrees to pay on demand all costs and expenses of the Agent in
connection with the preparation, execution and delivery of this
Amendment and the other instruments and documents to be delivered
hereunder, including the reasonable fees and out-of-pocket
expenses of counsel for the Agent with respect thereto and with
respect to advising the Agent as to its rights and
responsibilities hereunder and thereunder.  In addition, the
Guarantor shall pay any and all stamp and other taxes payable or
determined to be payable in connection with the execution and
delivery of this Amendment and the other instruments and
documents to be delivered hereunder, and the Guarantor agrees to
save the Agent and each Bank harmless from and against any and
all liabilities with respect to or resulting from any delay in
paying or omission to pay such taxes.

          Section 6.  Execution in Counterparts.  This Amendment
may be executed in any number of counterparts and by the parties
hereto in separate counterparts, each of which when so executed
and delivered shall be deemed to be an original and all of which
taken together shall constitute one and the same instrument.

          Section 7.  Governing Law.  THIS AMENDMENT SHALL BE
GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE
STATE OF CALIFORNIA APPLICABLE TO CONTRACTS MADE AND PERFORMED IN
THE STATE OF CALIFORNIA.


FRONTIER OIL CORPORATION


By:  /s/ Jon D. Galvin
- ------------------------------
Jon D. Galvin
Vice President and Chief Financial Officer



UNION BANK, as Agent and as a Bank

By:  /s/ Richard P. DeGrey, Jr.
- ------------------------------
Richard P. DeGrey, Jr.
Vice President


By:  /s/ John M. Edmonston
- ------------------------------
Name:  John M. Edmonston
Title:  Vice President



Each of the undersigned hereby consents to
the foregoing Amendment as of the date
first written above:


FRONTIER OIL AND REFINING COMPANY


By:  /s/ Jon D. Galvin
- ------------------------------
Jon D. Galvin
Vice President and Chief Financial Officer



WAINOCO OIL CORPORATION


By:  /s/ Julie H. Edwards
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Julie H. Edwards
Vice President, Secretary and Treasurer



FRONTIER HOLDINGS INC.


By: /s/ Jon D. Galvin
- ------------------------------
Jon D. Galvin
Vice President and Chief Financial Officer



FRONTIER REFINING INC.


By:  /s/ Jon D. Galvin
- ------------------------------
Jon D. Galvin
Vice President and Chief Financial Officer



FRONTIER PIPELINE INC.


By:  /s/ Jon D. Galvin
- ------------------------------
Jon D. Galvin
Vice President



FRONTIER PRODUCTS INC.


By:  /s/ Jon D. Galvin
- ------------------------------
Jon D. Galvin
Vice President