EXHIBIT 21 SUBSIDIARIES OF UNOCAL CORPORATION Name of Company (a) Organized under Law of - ----------------------------------------------------------------------------------------------------------- Union Oil Company of California, dba "UNOCAL" California Philippine Geothermal, Inc. California Unocal Geothermal of Indonesia, Ltd. Bermuda Unocal International Corporation Nevada Unocal Canada Limited Alberta Unocal Canada Resources (b) Alberta Unocal Canada Exploration Limited Alberta Unocal Canada International Company Nova Scotia Unocal Canada Management Limited Alberta Unocal Indonesia, Ltd. Bermuda Unocal Indonesia Company (c) Bermuda Unocal Netherlands B.V. Netherlands Unocal Thailand, Ltd. Bermuda - ------------------------------------------------------------------------------------------------------------ (a) The indented companies are subsidiaries of Union Oil Company of California. The names of approximately 190 subsidiaries are omitted inasmuch as such subsidiaries, considered in the aggregate as a single subsidiary, would not constitute a significant subsidiary. (b) Owned 89.5 percent by Unocal Canada Limited, 5.6 percent by Unocal Canada Exploration Limited and 4.9 percent by Unocal Canada Management Limited. (c) Owned 53.1 percent by Unocal Indonesia, Ltd. and 46.9 percent by Unocal Canada International Company.