EX-21 11 ex21-1.htm EXHIBIT 21.1 EXHIBIT 21.1

FRONTIER OIL CORPORATION
LIST OF SUBSIDIARIES OF THE REGISTRANT

Frontier Oil Corporation (incorporated in Wyoming)

662712 Alberta Ltd. (incorporated in Alberta)

Wainoco Resources, Inc. (incorporated in Delaware),
a subsidiary of Frontier Oil Corporation.

Wainoco Oil & Gas Company (incorporated in Delaware),
a subsidiary of Wainoco Resources, Inc.

Frontier Holdings Inc. (incorporated in Delaware),
a subsidiary of Frontier Oil Corporation.

Frontier Refining & Marketing Inc. (incorporated in Delaware),
a subsidiary of Frontier Holdings Inc.

Frontier Refining Inc. (incorporated in Delaware),
a subsidiary of Frontier Refining & Marketing Inc.

Frontier Oil and Refining Company (incorporated in Delaware),
a subsidiary of Frontier Refining & Marketing Inc.

Frontier Pipeline Inc. (incorporated in Delaware),
a subsidiary of Frontier Refining & Marketing Inc.

Frontier El Dorado Refining Company (incorporated in Delaware),
a subsidiary of Frontier Refining & Marketing Inc.