Exhibit 21 BARRETT RESOURCES CORPORATION Subsidiaries of the Registrant Name of Company State of Incorporation - --------------- ---------------------- Advantage Resources International, Inc. Peru........ Colorado Alarado Corporation.................................. Delaware Alarado (Denver) Company............................. Colorado Bargath, Inc......................................... Colorado Barrett 1997 Trust (a business trust)................ Delaware Barrett Fuels Corporation............................ Delaware Barrett Piceance LLC (a limited liability company)... Colorado Barrett Resources International Corporation.......... Delaware Barrett Resources (PAC I) Corporation................ Kansas Barrett Resources (PAC II) Corporation............... Kansas Barrett Resources (Peru) Corporation................. Delaware BGP, Inc............................................. Delaware Grand Valley Gathering System (joint venture)........ Colorado Plains Petroleum Company............................. Delaware Plains Petroleum Gathering Company................... Delaware Plains Petroleum Operating Company................... Delaware All of the subsidiaries named above are included in the consolidated financial statements of the Registrant included herein.