EXHIBIT 21 SUBSIDIARIES OF RPC, INC. NAME STATE OF INCORPORATION ---- ---------------------- Cudd Pressure Control, Inc. Delaware Pressure Control, Inc. Delaware South Texas Swabbing, Inc. Texas Coiled Tubing, Inc. Delaware Patterson Services, Inc. Delaware Patterson Truck Line, Inc. Louisiana Patterson Tubular Services, Inc. Texas Chaparral Boats, Inc. Georgia RPC Investment Company Delaware RPC Waste Management Services, Inc. Georgia Anchor Crane & Hoist Service Company, Inc. Georgia RPC Data Link, Inc. Georgia