SECURITIES AND EXCHANGE COMMISSION
                        Washington, D.C. 20549
                                   
                              FORM 10-K
            ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                OF THE SECURITIES EXCHANGE ACT OF 1934
[x]         FOR THE FISCAL YEAR ENDED:  DECEMBER 31, 1998
                                  OR
          TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)
                OF THE SECURITIES EXCHANGE ACT OF 1934
[ ]       For the transition period from . . . . to . . . .

                   Commission File Number:  1-7627

                       FRONTIER OIL CORPORATION
        (Exact name of registrant as specified in its charter)

         WYOMING                                   74-1895085
(State or other jurisdiction of                 (I.R.S. Employer
incorporation or organization)                 Identification No.)

10000 MEMORIAL DRIVE, SUITE 600                    77024-3411
     HOUSTON, TEXAS                                (Zip Code)
(Address of principal executive offices)

 Registrant's telephone number, including area code:  (713) 688-9600
     Securities registered pursuant to Section 12(b) of the Act:

                                              Name of Each Exchange
   Title of Each Class                         on Which Registered
   -------------------                       ----------------------

Common Stock                                 New York Stock Exchange
                                                        
9-1/8% Senior Notes, due 2006                New York Stock Exchange


     Securities registered pursuant to Section 12(g) of the Act:
                                 None

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.
                          Yes [x]  No . . .

Indicate by check mark if disclosure of delinquent filers pursuant to rule 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K.{ }
                                   
                                   
As of February 24, 1999 there were 27,602,594 common shares outstanding, and the
aggregate market value of the common shares (based upon the closing price of
these shares on the New York Stock Exchange) of Frontier Oil Corporation held by
nonaffiliates was approximately $147 million at that date.

                 DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Annual Report to Shareholders for the year ended December 31,
1998 are incorporated by reference into Item 1 of Part 1 and Items 5 through 8
of Part II.

Portions of the Annual Proxy Statement for the year ended December 31, 1998 are
incorporated by reference into Items 10 through 13 of Part III.

<PAGE>

TABLE OF CONTENTS

Part I 
 Item 1. Business                                                      1
 Item 2. Properties                                                    7
 Item 3. Legal Proceedings                                             8
 Item 4. Submission of Matters to a Vote of Security Holders           8

Part II
 Item 5. Market for the Registrant's Common Stock and
          Related Stockholder Matters                                  9
 Item 6. Selected Financial Data                                       9
 Item 7. Management's Discussion and Analysis of Financial Condition
          and Results of Operations                                    9
 Item 8. Financial Statements and Supplementary Data                   9
 Item 9. Changes in and Disagreements with Accountants on
          Accounting and Financial Disclosure                          9

Part III
 Item 10. Directors and Executive Officers of the Registrant           9
 Item 11. Executive Compensation                                       9
 Item 12. Security Ownership of Certain Beneficial Owners and
           Management                                                  9
 Item 13. Certain Relationships and Related Transactions               9

Part IV
 Item 14. Exhibits, Financial Statements Schedules, and Reports
           on Form 8-K                                                 9
                                                                      


FORWARD-LOOKING STATEMENTS

This Form 10-K contains "forward-looking statements" within the meaning of
Section 27A of the Securities Act, as amended, and Section 21E of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), including, without
limitation, statements that include the words "anticipates," "believes,"
"could," "estimates," "expects," "intends," "may," "plan," "predict," "project,"
"should," and similar expressions, and statements relating to the Company's
strategic plans, capital expenditures, industry trends and prospects and the
Company's financial position.  Such forward-looking statements involve known and
unknown risks, uncertainties and other factors that may cause actual results,
performance or achievements of the Company to differ materially from those
expressed or implied by such forward-looking statements.  Although the Company
believes that its plans, intentions and expectations reflected in such
forward-looking statements are reasonable, it can give no assurance that such
plans, intentions or expectations will be achieved. Important factors that could
cause actual results to differ materially from the Company's expectations
("Cautionary Statements") are set forth under the captions "Business" and
"Management's Discussion and Analysis of Financial Condition and Results of
Operations," and elsewhere in this document.  All subsequent written and oral
forward-looking statements attributable to the Company or persons acting on its
behalf are expressly qualified in their entirety by the Cautionary Statements.


PART 1

ITEM 1. BUSINESS

OVERVIEW

   Frontier Oil Corporation (formerly known as Wainoco Oil Corporation) was
originally incorporated in Canada in 1949 and changed its jurisdiction of
incorporation to Wyoming in 1976.  As used herein, the "Company" or "Frontier"
refers to Frontier Oil Corporation and its subsidiaries.  The Company's refining
assets are held through its subsidiary, Frontier Holdings Inc. ("Frontier
Holdings"), a Delaware corporation.  The Company directs its activities from its
corporate office in Houston, Texas and its refining subsidiary offices in
Denver, Colorado and Cheyenne, Wyoming.

   Frontier is engaged in the business of crude oil refining and wholesale
marketing of refined petroleum products

                                    - 1 -

<PAGE>

(the "refining operations").  Frontier conducts its refining operations in the
Rocky Mountain region of the United States. The Company's Cheyenne, Wyoming
refinery (the "Frontier Refinery") purchases the crude oil to be refined and
markets the refined petroleum products produced, including various grades of
gasoline, diesel fuel, asphalt and petroleum coke.

   Prior to the third quarter of 1997, Frontier explored for and produced oil
and gas in western Canada.  On June 16, 1997, Frontier completed the sale of all
its Canadian oil and gas properties.  Prior to their sale in June 1997, the
Company's Canadian oil and gas assets were held by Frontier Oil Corporation.
Prior to the first quarter of 1996, Frontier also explored for and produced oil
and gas in the United States. During the third quarter of 1994, the Company
announced that it intended to cease all exploration activities in the United
States and to sell its United States oil and gas assets.  Frontier finalized the
sale of all of its United States oil and gas properties during 1995.

   Operating results for the Company's discontinued oil and gas operations
segment, comprising the Canadian and United States oil and gas properties, are
presented as discontinued operations in the Financial Statements to the 1998
Annual Report to Shareholders which is incorporated herein by reference.
   
REFINING OPERATIONS

   Frontier's refining activities are conducted through its subsidiary Frontier
Holdings, which was acquired in October 1991.  The Frontier Refinery's permitted
crude capacity is 41,000 barrels per day ("bpd").  The Frontier Refinery can
also process in excess of 4,000 bpd of purchased natural gasoline, butanes and
other petroleum liquids. The Frontier Refinery contains all of the major
refinery units that comprise a complex refinery, including a coker. Therefore,
the Frontier Refinery has the capability of producing a high yield of lighter,
more valuable petroleum products such as gasoline and diesel fuel from heavy
sour crude oil, which is less expensive than lighter sweet crude oil.  The
Frontier Refinery's units have the capacity to process up to 100% of heavy crude
oil.  The differential between the price of lower cost heavy crude oil and the
price of more expensive lighter sweet crude oil is referred to as the
light/heavy spread.  Frontier also owns an undivided interest equal to 25,000
bpd in a crude oil pipeline (the "Centennial Pipeline") from Guernsey, Wyoming
to Cheyenne.  The Centennial Pipeline was constructed to help serve the Frontier
Refinery's long-term strategic crude oil needs.

MARKETING, PRODUCTS AND DISTRIBUTION

   The Company markets refined products primarily in eastern Colorado (including
the Denver metropolitan area) and eastern Wyoming, or the "Eastern Slope area"
of the Rocky Mountain region. The Company also markets refined products in
western Nebraska and, through exchange agreements with other refiners, in the
Dakotas and Utah.  For the year ended December 1998, the Frontier Refinery's
product mix included various grades of gasoline (40%), diesel fuel (34%) and
asphalt and other refined petroleum products (26%).

   The Company sells refined products to a broad base of independent retailers,
jobbers and major oil companies. Prices are determined by local market
conditions at the "terminal rack", and the customer typically supplies their own
truck transportation.  In 1998, approximately 10% of gasoline production and
approximately 49% of diesel production was sold at the Frontier Refinery.  The
remaining gasoline and diesel produced by the Frontier Refinery is primarily
shipped via pipeline to third party terminals for sale.

   While it has in the past generally marketed unbranded products, in the second
half of 1997, the Company entered into a seven-year marketing agreement with
CITGO Petroleum Corporation ("CITGO") to market branded products to independent
and other branded retail operators in its market area.  The Company believes the
CITGO agreement offers potential to increase its market share in the Eastern
Slope area because CITGO currently has only a small share of the Eastern Slope
market.  The agreement allows the Company to produce gasoline and diesel to
CITGO's specifications, sign up independent and other branded retail operators
as CITGO branded locations and sell its own refined products to these operators.
The agreement also allows the Company to offer additional benefits to its
customers such as access to CITGO's proprietary credit card and pay-at-the-pump
systems.  Moreover, the Company believes that its affiliation with the
nationally-recognized CITGO brand will allow it to continue to effectively
compete in its market area as more independent regional retailers seek
relationships with suppliers of branded products.

CRUDE OIL SUPPLY

   The Company prefers to process locally produced heavy crude oil.  In the year
ended December 31, 1998, the Company obtained approximately 57% of its crude oil
supply, or charge, from Wyoming producers while Canadian heavy crude oil made up
a majority of the Frontier Refinery's remaining feedstocks.  During the same
period, heavy crude oil constituted approximately 94% of the Frontier Refinery's
total crude oil charge.  The Company believes it is able to obtain favorable
pricing terms for the heavy crude oil it uses as feedstock because until the
last half of 1998 available supply outstripped demand.  None of the Company's
direct refinery competitors and only three other refineries

                                    - 2 -

<PAGE>

in the entire Rocky Mountain region operate coking units necessary to process
high volumes of heavy crude oil.  The Company benefitted from an increase in its
light/heavy spread to $4.15 per barrel ("bbl") for the year ended December 1998
from $3.54 per bbl for the same period in 1997. Throughout 1998, and especially
during the second half of 1998, the price of crude oil has declined
significantly.  The low price of crude oil has caused the production of some
heavy crude oil in both Wyoming and Canada to become uneconomical.  The reduced
supply of heavy crude oil and strong demand for heavy crude oil due to
attractive asphalt margins are major factors contributing to the second half of
1998 decline in the light/heavy spread.  In addition, while Wyoming crude oil
production is declining, the completion of the 785 mile Express Pipeline from
Hardisty, Alberta to Casper, Wyoming in April 1997 immediately doubled available
pipeline capacity for Canadian crude oil to the Wyoming market.  The Express
Pipeline has reduced transportation costs incurred by the Company for Canadian
crude oils by approximately $.75 per bbl, and the Company believes the Express
Pipeline has reduced transportation time for Canadian crude oils from
approximately 30 days to 15 days.  The Company has entered into a 15 year
commitment with the Express Pipeline for the delivery of approximately 13,800
bpd, subject to an assignment of a portion of the capacity in early years for
additional capacity in later years.  The Company also receives a supply cost
advantage on up to 25,000 bpd from its partial ownership in the Centennial
Pipeline that runs from the regional hub at Guernsey, Wyoming to the Frontier
Refinery.

COMPETITION 

   Frontier's business is highly competitive and price is the principal basis of
competition.  There are 15 crude oil refineries in the Rocky Mountain region
(including several owned by major integrated oil companies).  Many of the
refineries in the Rocky Mountain region are owned by companies that have
significantly greater financial resources and/or refining capacity than
Frontier.  Certain of these competitors, as integrated oil companies, also have
the advantage of owning or controlling crude oil reserves or other sources of
crude oil supply, crude oil and product pipelines and service stations and other
product marketing outlets.

   Principal Competitors.  Of the 15 crude oil refineries in the Rocky Mountain
region, the Company only considers the four other refineries (two in Denver and
two in Wyoming) located within the Eastern Slope area to be competitors,
although additional competition comes from refineries outside the Eastern Slope
area that supply refined products to the area via pipeline.  Based on proximity
to the Denver and Cheyenne areas, Frontier's principal refinery  competitors in
the wholesale segment are Sinclair Oil Company ("Sinclair") with a 54,000 bpd
refinery near Rawlins, Wyoming and a 22,000 bpd refinery in Casper, Wyoming,
Ultramar Diamond Shamrock ("UDS") with a 28,000 bpd refinery in Denver, Colorado
and Conoco, Inc. ("Conoco") with a 57,500 bpd refinery in Denver, Colorado.
Frontier sells its products exclusively at wholesale, principally to independent
retailers, jobbers and major oil companies, while Sinclair, UDS and Conoco
service both the retail and wholesale markets.  In addition, three product
pipelines from outside the Rockies terminate in the area.  The Company believes
it has an advantage over (i) its four refinery competitors because only the
Company operates a coking unit, which enables it to produce a higher yield of
gasoline and diesel from heavy crude oil, and (ii) the pipeline competitors that
ship product into the Eastern Slope area because they must incur a
transportation cost, which for Gulf Coast refiners equates to approximately
$1.60 per bbl.

   Frontier and its principal competitors all service the Denver market. Because
their refineries are located in Denver, UDS's and Conoco's product
transportation costs in servicing that area are lower than those of Frontier.
Conversely, Frontier has lower crude transportation costs due to its proximity
to Guernsey, Wyoming, the major crude oil pipeline hub in the Rocky Mountain
region, and further due to its ownership interest in the Centennial Pipeline.

   General.  Frontier competes with other oil and gas concerns and other
investment opportunities, whether or not related to the petroleum industry, in
raising capital.  The Company's ability to compete successfully in the capital
markets is largely dependent on the success of its refining activities and the
economic environment in which it operates.

VOLATILITY OF CRUDE OIL PRICES AND REFINING MARGINS

   Frontier's income and cash flow are derived from the margin between its costs
to obtain and refine crude oil and the price for which it can sell products
produced in its refining process. The price at which Frontier can sell gasoline
and its other refined products will be strongly influenced by the price of crude
oil.  Frontier maintains inventories of crude oil, intermediate products and
refined products, the value of each of which is subject to rapid fluctuations in
market prices.  Inventories are recorded at the lower of cost on a first in,
first out ("FIFO") basis or market.  A rapid and significant movement in the
market prices for crude oil or refined products could have an adverse short-term
impact on earnings and cash flow.  The Company generally does not hedge its
refined product prices.  Crude oil prices, in general, are affected by a number
of factors, including domestic and international demand, domestic and foreign
energy legislation, production guidelines established by the Organization of
Petroleum Exporting Countries ("OPEC"), relative supplies of other fuels, such
as natural gas, and changing international economic and political conditions.

                                    - 3 -

<PAGE>

LIGHT/HEAVY CRUDE OIL SPREAD

   Frontier can process a high percentage of heavy crude oil, enabling it to
benefit from the lower cost of heavy crude relative to light crude.  Because
income and cash flow from refining operations are dependent in part on this cost
differential, any narrowing of the light/heavy crude spread would likely cause a
reduction in operating margin and a decrease in earnings and cash flow of
Frontier.  A narrowing of the light/heavy crude spread could result from, among
other things, a decrease in the supply of heavy crude due to a substantial drop
in crude oil prices that could depress the spread by making it uneconomical for
production companies to produce heavy crude oil or an increase in heavy crude
refining capacity of the Frontier's competitors.

GOVERNMENT REGULATION

   Safety Matters.  The Company is subject to the requirements of the federal
Occupational Safety and Health Act ("OSHA") and comparable state occupational
safety statutes.  The Company believes that it has operated in substantial
compliance with OSHA requirements, including general industry standards,
recordkeeping and reporting, hazard communication, and process safety
management.  The nature of the Company's business may result from time to time
in industrial accidents.  It is possible that changes in safety and health
regulations or a finding of non-compliance with current regulations could result
in additional capital expenditures or operating expenses.

   Environmental Matters.  The Company's refining and marketing operations are
subject to a variety of federal, state and local health and environmental laws
and regulations governing product specifications, the discharge of pollutants
into the air and water, and the generation, treatment, storage, transportation
and disposal of solid and hazardous waste and materials.  Permits are required
for the operation of the Frontier Refinery, and these permits are subject to
revocation, modification and renewal.  Governmental authorities have the power
to enforce compliance with these regulations and permits, and violators are
subject to injunctions, civil fines and even criminal penalties.  The Company
believes the Frontier Refinery is in substantial compliance with existing
environmental laws, regulations and permits.

   Among these requirements are regulations recently promulgated by the EPA
under the authority of Title III of the Clean Air Act Amendments.  The Title III
regulations required the Company to expend approximately $600,000 by the
regulatory compliance deadline of August 1, 1998 to improve the Frontier
Refinery's control of emissions of hazardous air pollutants.  Subsequent
rulemaking authorized by this or other titles of the Clean Air Act Amendments or
similar laws may necessitate additional expenditures in future years. Because
other refineries will be required to make similar expenditures, the Company does
not expect such expenditures to materially adversely impact its competitive
position.

   Nevertheless, rules and regulations implementing federal, state and local
laws relating to health and the environment will continue to affect operations
of the Company, and the Company cannot predict what additional health and
environmental legislation or regulations will be enacted or become effective in
the future or how existing or future laws or regulations will be administered or
interpreted with respect to products or activities to which they have not been
applied previously.  Compliance with more stringent laws or regulations, as well
as more vigorous enforcement policies of regulatory agencies, could have a
materially adverse effect on the financial position and the results of
operations of the Company as well as the refining industry in general, and may
result in substantial expenditures for the installation and operation of
pollution control or other environmental systems and equipment.

   On March 21, 1995, the Company and the Wyoming Department of Environmental
Quality entered into an administrative consent order ("State Order") that
generally parallels a September 24, 1990 Administrative Order on Consent
("Federal Order") pursuant to the Resource Conservation and Recovery Act
("RCRA") and replaces the 1984 state consent decree ("Consent Decree").
Accordingly, the Consent Decree was dismissed in an Order entered March 21,
1995.  The State Order eliminates certain of the Consent Decree requirements,
unifies state and federal regulatory expectations regarding site investigation
and remediation and, consequently, helps to streamline certain of the Company's
current environmental obligations. The EPA withdrew the Federal Order on March
19, 1997 in recognition of the State Order and of Wyoming's assumption of RCRA
corrective action authority.  The ultimate cost of any environmental remediation
projects that may be identified by the site investigation required by the State
Order cannot be reasonably estimated at this time.  However, the continuation of
the present investigative process, other more extensive investigations over time
or changes in regulatory requirements could result in future liabilities.

   The Company has a 34.72% undivided ownership interest in the Centennial
Pipeline.  Conoco Pipe Line Company is the sole operator of the Centennial
Pipeline as the holder of the remaining ownership interest.  The Centennial
Pipeline runs approximately 88 miles from Guernsey to Cheyenne, Wyoming.  The
Frontier Refinery receives up to 25,000 bpd of crude oil feed through the
Centennial Pipeline. Under the terms of the operating agreement for the
Centennial Pipeline, the costs and expenses incurred to operate and maintain the
Centennial Pipeline are allocated to the Company on the basis of either its
throughput or ownership interest. The Centennial Pipeline is subject to

                                    - 4 -

<PAGE>

numerous federal, state and local laws and regulations relating to the
protection of health, safety and the environment. The Company believes the
Centennial Pipeline is operated in accordance with all applicable laws and
regulations.  The Company is not aware of any material pending legal proceedings
to which the Centennial Pipeline  is a party.

   In 1997, the Company completed divesting itself of its former oil and gas
properties and assets.  While the transactions that conveyed these properties
and assets to new owners were intended to transfer any attendant environmental
liabilities to new owners, there can be no assurances that the Company will
never be subject to liability for any former activity respecting the divested
oil and gas properties.  The Company has been named as a potentially responsible
party ("PRP") under CERCLA (as defined herein) at the Gulf Coast Vacuum Services
Superfund Site located in Vermilion Parish, Louisiana, one of the divested
properties.  The Company has entered into a consent decree resolving its
liabilities as a PRP at this Superfund site.  The Company believes that any
future liabilities related to this site will not have a material adverse effect
on the financial condition of the Company.  The Company also believes that any
liability relating to its historical practices respecting the oil and gas
properties will not have a material adverse effect on the financial condition of
the Company.

   The Comprehensive Environmental Response, Compensation and Liability Act
("CERCLA"), also known as "Superfund", imposes liability, without regard to
fault or the legality of the original conduct, on certain classes of persons who
are considered to be responsible for the release of a "hazardous substance" into
the environment.  These persons include the owner or operator of the disposal
site or sites where the release occurred and companies that disposed or arranged
for the disposal of the hazardous substances.  Under CERCLA, such persons may be
subject to joint and several liability for the costs of cleaning up the
hazardous substances that have been released into the environment, for damages
to natural resources, and for the costs of certain health studies.  It is not
uncommon for neighboring landowners and other third parties to file claims for
personal injury and property damage allegedly caused by hazardous substances or
other pollutants released into the environment. Analogous state laws impose
similar responsibilities and liabilities on responsible parties.  In the course
of its historical operations, as well as in its current ordinary operations, the
Company has generated waste, some which falls within the statutory definition of
a "hazardous substance" and some of which may have been disposed of at sites
that may require cleanup under Superfund.

   As is the case with all companies engaged in similar industries, the Company
faces potential exposure from future claims and lawsuits involving environmental
matters.  These matters include soil and water contamination, air pollution, and
personal injuries or property damage allegedly caused by substances
manufactured, handled, used,  released or disposed of by the Company.

   Product Specifications.  The provisions of the Clean Air Act Amendments of
1990 requiring the EPA to reassess the adequacy of existing limits on automobile
emissions, coupled with the recent promulgation of new National Ambient Air
Quality Standards ("NAAQS") for ozone and particulate matter have resulted, in
part, in initial state and federal agency consideration of requirements to
modify certain transportation fuel characteristics including, but not limited
to, gasoline sulfur content and vapor pressure.  Although no such regulations
have yet been proposed, Frontier may in the future incur certain, as yet
unquantified, costs necessary to assure compliance.

SEASONALITY

   Due to seasonal increases in tourist related volume and road construction
work, a higher demand exists in the Rocky Mountain region for gasoline and
asphalt products during the summer months than during the winter months. Diesel
demand is relatively constant throughout the year because two major east-west
truck routes, and at least two railroads, extend into or through Frontier's
principal marketing area. However, reduced road construction and agricultural
work during the winter months does somewhat reduce demand for diesel.  As a
result, the Company's operating results for the first and fourth calendar
quarters are generally lower than those for the second and third calendar
quarters.  The Frontier Refinery normally schedules its maintenance turnaround
work during the spring or fall of each year.  During the first quarter of 1999,
Frontier has scheduled turnaround work on its crude unit.

                                    - 5 -

<PAGE>

OPERATING HAZARDS; SINGLE REFINERY 

   All of the Company's refining activities currently are conducted at the
Frontier Refinery, which is the Company's principal operating asset.  As a
result, the operations of the Company are subject to significant interruption if
the Frontier Refinery were to experience a major accident or fire, be damaged by
severe weather or other natural disaster, or otherwise be forced to curtail its
operations or shutdown.  Should the Centennial Pipeline, which runs from the
Guernsey Station hub to the Frontier Refinery, become inoperative, crude oil
would have to be supplied to the Frontier Refinery through an alternative
pipeline or from additional tank trucks, the economic impact of which could be
adverse to the Company.  In addition, despite safety procedures put in place by
the Company, a major accident, fire or other event could damage the Frontier
Refinery or the environment or cause personal injuries.  Although the Company
maintains business interruption, property and other insurance against these
risks in amounts it believes to be economically prudent, if the Frontier
Refinery were to experience a major accident or fire or an interruption in
supply or operations, the Company's business could be materially adversely
affected.  In addition, the Frontier Refinery consists of many processing units,
a number of which have been in operation for a long time. Although the Company
schedules down time for repair, or "turnaround," for each unit every one to
three years, there can be no assurance that one or more of such units will not
require additional, unscheduled turnarounds for unanticipated maintenance or
repairs.  During the first quarter of 1999, the Company has scheduled a
turnaround on one of its major units at the Frontier Refinery.
 
EMPLOYEES

   At December 31, 1998 the Company employed 298 full-time employees, 46 at the
Houston and Denver offices and 252 at the Frontier Refinery.  The Frontier
Refinery employees include 83 administrative and technical personnel and 169
union members.  The union members are represented by seven bargaining units, the
largest being the Paper, Allied-Industrial, Chemical and Energy Workers
International Union ("PACE"). Six AFL-CIO affiliated unions represent Frontier's
craft workers.  In December 1998, the Company concluded new bargaining
agreements, with the three year PACE agreement due to expire in July 1999
extended to July 2002, while the six year AFL-CIO contract due to expire in June
2002 extended to June 2005.  The Company considers its current relations with
its employees to be good.

                                    - 6 -

<PAGE>

ITEM 2. PROPERTIES
    

REFINING OPERATIONS

   The refining facilities are located on approximately 125 acres in Cheyenne,
Wyoming, on property owned by Frontier.  The following table sets forth the
Frontier Refinery's charges, yields and margins achieved for the past three
years:

<TABLE>
<CAPTION>

Year Ended December 31,                              1998       1997       1996
                                                  ---------  ---------  ---------
<S>                                               <C>        <C>        <C>

Charges (bpd)
 Light crude                                          2,174      3,162      4,322
 Heavy crude                                         32,303     31,967     31,677
 Other feed and blend stocks                          5,909      6,154      5,192
                                                  ---------  ---------  ---------
  Total                                              40,386     41,283     41,191

Manufactured product yields (bpd)
 Gasoline                                            15,738     17,060     16,825
 Diesel                                              13,097     12,856     13,712
 Asphalt and other                                   10,236     10,200      9,215
                                                  ---------  ---------  ---------
  Total                                              39,071     40,116     39,752

Total product sales (bpd)
 Gasoline                                            21,421     20,499     20,311
 Diesel                                              12,484     12,110     12,561
 Asphalt and other                                    8,797      7,949      7,306
                                                  ---------  ---------  ---------
  Total                                              42,702     40,558     40,178

Operating margin information (per sales bbl)
 Average sales price                              $   19.10  $   25.27  $   25.98
 Material costs (under FIFO inventory accounting)     13.01      19.49      21.50
                                                  ---------  ---------  ---------
  Product spread                                       6.09       5.78       4.48
 Operating expenses excluding depreciation             3.34       3.30       3.15
 Depreciation                                           .68        .61        .59
                                                  ---------  ---------  ---------
  Operating margin                                $    2.07  $    1.87  $     .74

Manufactured product margin
  before depreciation (per bbl)                   $    2.80  $    2.47  $    1.33

Purchased product margin
  (per purchased product bbl)                     $    1.62  $    3.14  $    2.03

Light/heavy crude spread (per bbl)                $    4.15  $    3.54  $    2.56

Average sales price (per sales bbl)
 Gasoline                                         $   21.52  $   28.83  $   28.78
 Diesel                                               19.90      27.22      28.89
 Asphalts and other                                   12.07      13.13      13.21

</TABLE>


OTHER PROPERTIES

   The Company leases approximately 4,600 square feet of office space in Houston
for its corporate headquarters under a six and one half  year lease expiring in
October 2004.  Frontier leases approximately 16,000 square feet in Englewood,
Colorado for its refining operations headquarters under a seven-year lease
expiring in July 2002.

                                    - 7 -

<PAGE>

ITEM 3. LEGAL PROCEEDINGS

   There are no legal proceedings which in the opinion of management would have
a material adverse impact on the Company.  See Item 1. Business - Government
Regulation regarding certain ongoing proceedings regarding environmental
matters.

ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

   None.

                                    - 8 -

<PAGE>

PART II

ITEM 5. MARKET FOR THE REGISTRANT'S COMMON STOCK AND RELATED STOCKHOLDER MATTERS

   The information in the 1998 Annual Report to Shareholders under the heading
"Common Stock" is incorporated herein by reference.

ITEM 6. SELECTED FINANCIAL DATA

   The information in the 1998 Annual Report to Shareholders under the heading
"Five Year Financial Data" is incorporated herein by reference.

ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
        RESULTS OF OPERATIONS

   The information in the 1998 Annual Report to Shareholders under the heading
"Management's Discussion and Analysis" is incorporated herein by reference.

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

   The financial statements and the data contained in the 1998 Annual Report to
Shareholders are incorporated herein by reference.  See index to financial
statements and supplemental data appearing under Item 14(a)1.

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
        FINANCIAL DISCLOSURE

   None.

PART III

   The information called for by Part III of this Form is incorporated by
reference from the Company's definitive proxy statement to be filed with the
Commission pursuant to Regulation 14A within 120 days after the close of its
last fiscal year.

PART IV

ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES, AND REPORTS ON FORM 8-K

(a)1. Financial Statements and Supplemental Data                 Page*
                                                                 -----

 Consolidated Statements of Operations                             17
 Consolidated Balance Sheets                                       18
 Consolidated Statements of Cash Flows                             19
 Consolidated Statements of Changes in Shareholders' Equity        20
 Notes to Consolidated Financial Statements                        21
 Report of Independent Public Accountants                          28
 Selected Quarterly Financial Data                                 13

 *Reference to pages in the 1998 Annual Report to Shareholders (as published),
 which portions thereof are incorporated herein by reference.

                                    - 9 -

<PAGE>

(a)2. Financial Statements Schedules

 Report of Independent Public Accountants
 Schedule I - Condensed Financial Information of Registrant           
 Other Schedules are omitted because of the absence of the conditions under
 which they are required or because the required information is included in the
 financial statements or notes thereto.

(a)3. List of Exhibits

*    3.1 - Articles of Domestication of the Company, as amended (filed as
           Exhibit 2.3 to Registration Statement No. 2-62518 and Exhibit 2.2 to
           Registration Statement No. 2-69149).

*    3.2 - Articles of Amendment to the Restated Articles of Incorporation of
           the Company (filed as Exhibit 3.2 to Registration Statement No.
           333-47745 dated May 4, 1998).

*    3.3 - Fourth restated By-Laws of the Company as amended through February
           20, 1992 (filed as Exhibit 3.2 to Form 10-K dated December 31, 1992).

*    4.1 - Indenture dated as of February 9, 1998 between the Company and Chase
           Bank of Texas, National Association, as Trustee relating to the
           Company's 9-1/8% Senior Notes due 2006 (filed as Exhibit 4.8 to
           Registration Statement No. 333-47745 dated May 4, 1998).

*   10.1 - Amended and Restated Revolving Credit and Letter of Credit Agreement
           dated June 30, 1997 among Frontier Oil and Refining Company, certain
           banks and Union Bank of California (filed as Exhibit 10.1 to Form
           10-K dated June 30, 1997).

*   10.2 - First Amendment to Amended and Restated Revolving Credit and Letter
           of Credit Agreement dated June 30, 1998 among Frontier Oil and
           Refining Company, certain banks and Union Bank of California (filed
           as Exhibit 10.01 to Form 10-Q dated June 30, 1998).

*   10.3 - Purchase and Sale Agreement, dated May 5, 1997, for the sale of
           Canadian oil and gas properties (filed as an Exhibit to From 8-K
           filed June 30, 1997).

*+  10.4 - The 1968 Incentive Stock Option Plan as amended and restated (filed
           as Exhibit 10.1 to Form 10-K dated December 31, 1987).

*+  10.5 - The 1977 Stock Option Plan as amended and restated (filed as Exhibit
           10.2 to Form 10-K dated December 31, 1989).

*+  10.6 - 1995 Stock Grant Plan for Non-employee Directors (filed as Exhibit
           10.14 to Form 10-Q dated June 30, 1995).

*+  10.7 - Wainoco Deferred Compensation Plan dated October 29, 1993 (filed as
           Exhibit 10.19 to Form 10-K dated December 31, 1994).

*+  10.8 - Wainoco Deferred Compensation Plan for Directors dated May 1, 1994
           (filed as Exhibit 10.20 to Form 10-K dated December 31, 1994).

*+  10.9 - Executive Employment Agreement dated April 2, 1998 between the
           Company and James R. Gibbs (filed as Exhibit 10.01 to Form 10-Q dated
           March 31, 1998).

*+ 10.10 - Executive Employment Agreement dated April 2, 1998 between the
           Company and Julie H. Edwards (filed as Exhibit 10.02 to Form 10-Q
           dated March 31, 1998).

*+ 10.11 - Executive Employment Agreement dated April 2, 1998 between the
           Company and S. Clark Johnson (filed as Exhibit 10.03 to Form 10-Q
           dated March 31, 1998).

*+ 10.12 - Executive Employment Agreement dated April 2, 1998 between the
           Company and J. Currie Bechtol (filed as Exhibit 10.04 to Form 10-Q
           dated March 31, 1998).

*+ 10.13 - Executive Employment Agreement dated April 2, 1998 between the
           Company and Gerald B. Faudel (filed as Exhibit 10.05 to Form 10-Q
           dated March 31, 1998).

*+ 10.14 - Executive Employment Agreement dated April 2, 1998 between the
           Company and Jon D. Galvin (filed as Exhibit 10.06 to Form 10-Q dated
           March 31, 1998).

    13.1 - Portions of the Company's 1998 Annual Report covering pages 9 through
           28.

    21.1 - Subsidiaries of the Registrant.

      23 - Consent of Arthur Andersen LLP.

      27 - Financial Data Schedule.

*  Asterisk indicates exhibits incorporated by reference as shown.
+  Plus indicates management contract or compensatory plan or arrangement.

                                    - 10 -

<PAGE>

(b)   Reports on Form 8-K

   No reports on Form 8-K have been filed by the Company during the fourth
quarter of 1998.

(c) Exhibits

   The Company's 1998 Annual Report is available upon request.  Shareholders of
the Company may obtain a copy of any other exhibits to this Form 10-K at a
charge of $.25 per page. Requests should be directed to:

    Larry Bell
    Corporate Communications
    Frontier Oil Corporation
    10000 Memorial Drive, Suite 600
    Houston, Texas 77024-3411

                                    - 11 -

<PAGE>

(d) Schedules

   Report of Independent Public Accountants on Financial Statement Schedules:

To Frontier Oil Corporation:

   We have audited in accordance with generally accepted auditing standards, the
financial statements included in Frontier Oil Corporation's annual report to
shareholders incorporated by reference in this Form 10-K, and have issued our
report thereon dated February 5, 1999.  Our audits were made for the purpose of
forming an opinion on those statements taken as a whole.  The schedule listed in
the index above is the responsibility of the Company's management and is
presented for purposes of complying with the Securities and Exchange
Commission's rules and is not part of the basic financial statements.  This
schedule has been subjected to the auditing procedures applied in the audit of
the basic financial statements and, in our opinion, fairly states in all
material respects the financial data required to be set forth therein in
relation to the basic financial statements taken as a whole.




ARTHUR ANDERSEN LLP


Houston, Texas
February 5, 1999

                                    -12 -

<PAGE>

FRONTIER OIL CORPORATION
CONDENSED FINANCIAL INFORMATION OF REGISTRANT
BALANCE SHEETS
AS OF DECEMBER 31,                                          SCHEDULE I
                                                                      
(in thousands)

<TABLE>
<CAPTION>

                                                         1998       1997
                                                      ---------  ---------
<S>                                                   <C>        <C>
 
ASSETS
Current Assets:
   Cash and cash equivalents                          $  33,234  $  20,283
   Receivables                                              248        121
   Other current assets                                      51      1,019
                                                      ---------  ---------
    Total current assets                                 33,533     21,423
                                                      ---------  ---------
Property, Plant and Equipment, at cost -
   Furniture, fixtures and other                            502        468
   Less - Accumulated depreciation                         (324)      (245)
                                                            178        223
Investment in Subsidiaries                              140,503    138,778
Other Assets                                              4,577      3,104
                                                      ---------  ---------
                                                      $ 178,791  $ 163,528
                                                      =========  =========

LIABILITIES AND SHAREHOLDERS' EQUITY
Current Liabilities:
   Accounts payable                                   $     454  $      52
   Other accrued liabilities                              3,162      2,336
                                                      ---------  ---------
    Total current liabilities                             3,616      2,388
                                                      ---------  ---------
Deferred Income Taxes                                       421        840
Deferred Revenues and Other                               1,830      1,061
Payable to Affiliated Companies                          32,571     32,733
Long-Term Debt                                           70,000     70,572

Shareholders' Equity                                     70,353     55,934
                                                      ---------  ---------
                                                      $ 178,791  $ 163,528
                                                      =========  =========

</TABLE>


The "Notes to Condensed Financial Information of Registrant" and the "Notes to
Financial Statements of Frontier Oil Corporation and Subsidiaries" are an
integral part of these financial statements.

                                    - 13 -

<PAGE>

FRONTIER OIL CORPORATION
CONDENSED FINANCIAL INFORMATION OF REGISTRANT
STATEMENTS OF OPERATIONS
FOR THE THREE YEARS ENDED DECEMBER 31,                      SCHEDULE I
                                                                      
(in thousands)

<TABLE>
<CAPTION>

                                                              1998       1997       1996
                                                           ---------  ---------  ---------
<S>                                                        <C>        <C>        <C>

Revenues:
  Equity in earnings of subsidiaries                       $  27,655  $  22,707  $   6,666
  Other income                                                   (43)       645          -
                                                           ---------  ---------  ---------
                                                              27,612     23,352      6,666
                                                           ---------  ---------  ---------

Costs and Expenses:
  Selling and general expenses                                 2,433      2,472      2,099
  Depreciation, depletion and amortization                        79         71         77
                                                           ---------  ---------  ---------
                                                               2,512      2,543      2,176
                                                           ---------  ---------  ---------

Operating Income                                              25,100     20,809      4,490
Interest Expense, net                                          6,132     12,997     16,134
                                                           ---------  ---------  ---------

Income (Loss) from Continuing
  Operations Before Income Taxes                              18,968      7,812    (11,644)
Provision (Benefit) for Income Taxes                             150          -          -
                                                           ---------  ---------  ---------

Income (Loss) From Continuing Operations                      18,818      7,812    (11,644)
Discontinued Operations:
  Income from oil and gas operations, net of taxes                 -      1,721      4,752
  Gain on disposal of Canadian oil and gas properties,
   net of taxes                                                    -     23,301          -                        -
  Recognition of cumulative translation adjustment                 -     (9,862)         -
                                                           ---------  ---------  ---------

Income (Loss) Before Extraordinary Item                       18,818     22,972     (6,892)

Extraordinary Loss on Retirement of Debt, net of taxes         3,013      3,917          -
                                                           ---------  ---------  ---------
  
Net Income (Loss)                                          $  15,805  $  19,055  $  (6,892)
                                                           =========  =========  =========

</TABLE>


The "Notes to Condensed Financial Information of Registrant" and the "Notes to
Financial Statements of Frontier Oil Corporation and Subsidiaries" are an
integral part of these financial statements.

                                    - 14 -
<PAGE>

FRONTIER OIL CORPORATION
CONDENSED FINANCIAL INFORMATION OF REGISTRANT
STATEMENTS OF CASH FLOW
FOR THE THREE YEARS ENDED DECEMBER 31,                        SCHEDULE I
                                                                      
(in thousands)

<TABLE>
<CAPTION>
                                                              1998       1997       1996
                                                           ---------  ---------  ---------
<S>                                                        <C>        <C>        <C>


Operating Activities
  Net income (loss)                                        $  15,805  $  19,055  $  (6,892)
  Equity in earnings of subsidiaries                         (27,655)   (22,707)    (7,653)
  Gain on disposal of Canadian oil and gas properties              -    (23,301)         -
  Recognition of cumulative translation adjustment                 -      9,862          -
  Extraordinary loss on retirement of debt                     3,013      3,917          -
  Depreciation, depletion and amortization                        79      3,919      8,200
  Deferred income taxes                                         (419)      (878)         -
  Other                                                        2,480     (3,232)      (931)
                                                           ---------  ---------  ---------
Net cash used by operating activities                         (6,697)   (13,365)    (7,276)
                                                           ---------  ---------  ---------

Investing Activities
  Additions to property, plant and equipment                     (34)    (3,333)    (8,989)
  Sale of Canadian oil and gas properties                          -     91,307          -
  Proceeds from sale of other properties                           -        259        990
  Acquisition costs and other                                      -       (849)       429
                                                           ---------  ---------  ---------
Net cash provided by (used by) investing activities              (34)    87,384     (7,570)
                                                           ---------  ---------  ---------

Financing Activities
  Long-term borrowings:
     9-1/8% Senior Notes                                      70,000          -          -
     12% Senior Notes                                              -      2,000      3,000
  Payments of debt:
     12% Senior Notes, including premium                     (25,423)   (74,932)         -
     7-3/4% Convertible debentures, including premium        (45,971)         -          -
     Subordinated debentures                                       -     (7,500)         -
  Debt issuance costs                                         (2,575)         -          -
  Issuance of common stock                                       816      3,109          -
  Purchase of treasury stock                                  (2,933)         -          -
  Change in intercompany balances, net                          (162)       (53)    (1,805)
  Dividends paid to Parent                                    25,930     21,122     12,902
  Other                                                            -          -        (11)
                                                           ---------  ---------  ---------
Net cash provided by (used by) financing activities           19,682    (56,254)    14,086
Effect of exchange rate changes on cash                            -        (10)        13
                                                           ---------  ---------  ---------

Increase (decrease) in cash and cash equivalents              12,951     17,755       (747)
Cash and cash equivalents, beginning of period                20,283      2,528      3,275
                                                           ---------  ---------  ---------

Cash and cash equivalents, end of period                   $  33,234  $  20,283  $   2,528
                                                           =========  =========  =========
</TABLE>


The "Notes to Condensed Financial Information of Registrant" and the "Notes to
Financial Statements of Frontier Oil Corporation and Subsidiaries" are an
integral part of these financial statements.

                                    - 15 -

<PAGE>

FRONTIER OIL CORPORATION
NOTES TO CONDENSED FINANCIAL INFORMATION OF REGISTRANT
DECEMBER 31, 1998                                           SCHEDULE I
                                                                      



(1)  General

  The accompanying condensed financial statements of Frontier Oil Corporation
(Registrant) should be read in conjunction with the consolidated financial
statements of the Registrant and its subsidiaries included in the Registrant's
1998 Annual Report to Shareholders.

(2)  Sale of oil and gas properties

  All of the Registrant's oil and gas properties were located in Canada.  On
June 16, 1997, the Company completed the sale of all its Canadian oil and gas
properties.  The contract purchase price of C$133.6 million was adjusted from
the January 1, 1997 effective date of the sale to June 16, 1997.  Net proceeds
after these adjustments, transaction expenses and severance costs were
approximately C$126.7 million (US$91.3 million) as of June 16, 1997.

  The Company's subsidiary, Wainoco Oil & Gas Company, ceased oil and gas
exploration activities in the United States in 1994 and sold all of its United
States oil and gas properties in 1994 and 1995.  Information relating to the
sales are disclosed in the "Notes to Financial Statements of Frontier Oil
Corporation and Subsidiaries."

  Operating results for the Company's oil and gas operations segment, comprising
the Canadian and United States oil and gas properties, are presented as
discontinued operations.

(3)  Long-term debt

  The components (in thousands) of long-term debt are as follows:

<TABLE>
<CAPTION>
                                                      1998       1997
                                                   ---------  ---------
<S>                                                <C>        <C>

       9-1/8% Senior Notes                         $  70,000  $       -
       12% Senior Notes                                    -     24,572
       7-3/4% Convertible Subordinated Debentures          -     46,000
                                                   ---------  ---------
                                                   $  70,000  $  70,572
                                                   =========  =========

</TABLE>
  
(4)  Five-year maturities of long-term debt

  The 9-1/8% Senior Notes are due 2006, until then there are no maturities of
long-term debt.

                                    - 16 -

<PAGE>


                              SIGNATURES

   Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized on the date indicated.


                       FRONTIER OIL CORPORATION




                       By: /s/ James R. Gibbs
                           -----------------------
                           James R. Gibbs
                           President
                           (chief executive officer)


Date: February 26, 1999
                                                                      
                      
   Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of Frontier Oil
Corporation and in the capacities and on the date indicated.



                                                                      
/s/ James R. Gibbs                           /s/ Paul B. Loyd, Jr.
-----------------------------------          -----------------------------
James R. Gibbs                               Paul B. Loyd, Jr.
President and Director                       Director
(chief executive officer)





/s/ Julie H. Edwards                         /s/ James S. Palmer
-----------------------------------          -----------------------------
Julie H. Edwards                             James S. Palmer
Senior Vice President - Finance and          Director
Chief Financial Officer
(principal financial officer)




/s/ Jon D. Galvin                            /s/ Derek A. Price
-----------------------------------          -----------------------------
Jon D. Galvin                                Derek A. Price
Vice President - Controller                  Director
(principal accounting officer)





/s/ Douglas Y. Bech                          /s/ Carl W. Schafer
-----------------------------------          -----------------------------
Douglas Y. Bech                              Carl W. Schafer
Director                                     Director


Date: February 25, 1999