EXHIBIT 21.1

LIST OF ALL DIRECT AND INDIRECT SUBSIDIARIES

1.	PDC MGMT. CO. (formerly SOTEX Exploration Company), a Texas corporation—100% Direct Subsidiary—1% general partner of Pioneer Drilling Services, Ltd.
2.	PDC Investment Corp., A Delaware corporation—100% Direct Subsidiary—99% limited partner of Pioneer Drilling Services, Ltd.
3.	Pioneer Drilling Services, Ltd. (formerly Pioneer Drilling Co., Ltd.), a Texas limited Partnership—100% Indirect Subsidiary—owned  by PDC MGMT. CO. (1%) and PDC Investment Corp. (99%).
4.	South Texas Drilling Company, a Texas corporation—100% Direct Subsidiary.
5.	South Texas Offshore Drilling Company, a Texas corporation—100% Direct Subsidiary.
6.	ST/1200, Inc., a Texas corporation—100% Direct Subsidiary.