Exhibit 21 SUBSIDIARIES OF THE REGISTRANT Percentage of Voting Securities Owned By Immediate Parent as of August 31, 1997 Consolidated subsidiaries of the Registrant (Jurisdiction of incorporation): Parker Drilling Company of South America, Inc. (Oklahoma) 100% Parker Drilling Company of Oklahoma, Inc. (Oklahoma) 100% Parker Technology, Inc. (Oklahoma) (1) 100% Vance Systems Engineering, Inc. (Texas) (2) 100% Parker Drilling Company International Limited (Nevada) (3) 100% Parker Drilling Company of New Guinea, Inc. (Oklahoma) 100% Parker Drilling Company Limited (Nevada) 100% Parcan, Limited (Nevada) (4) 100%
Certain subsidiaries have been omitted from the list since they would not, even if considered in the aggregate, constitute a significant subsidiary. All subsidiaries are included in the consolidated financial statements. - ------------------------------------------------------------------------------- (1) Parker Technology, Inc. owns 100% of two subsidiary corporations, namely: Parco Masts and Substructures, Inc. (Oklahoma) Parker Valve Company (Texas) (2) Vance Systems Engineering, Inc. owns 100% of Parker Drilling Company Limited (Bahamas) and 93% of Parker Drilling Company Eastern Hemisphere, Ltd. (Oklahoma). Parker Drilling Company Limited owns 7% of Parker Drilling Company Eastern Hemisphere, Ltd. (Oklahoma). (3) Parker Drilling Company International Limited owns 100% of three subsidiary corporations, namely: Parker Drilling Company of New Zealand Ltd. (Oklahoma) Choctaw International Rig Corp. (Nevada) (which owns 100% of the common stock of Parker Drilling Company of Indonesia, Inc. (Oklahoma)) Creek International Rig Corp. (Nevada) (4) Parcan, Limited owns 100% of Parker Drilling U.S.A. Ltd (Nevada) and 50% of Parker Drilling Company North America, Inc. (Nevada). Parker Drilling U.S.A. Ltd. owns 99% of Mallard Bay Drilling, L.L.C. (Oklahoma), Quail Tools, L.L. P. (Oklahoma) and Parker Technology, L.L.C. (Louisiana) and 100% of eight less significant subsidiaries.