Patterson-UTI Reports Drilling Activity for December 2009

PATTERSON-UTI ENERGY, INC. (Nasdaq: PTEN) today reported that for the month of December 2009, the Company had an average of 118 drilling rigs operating, including 108 rigs in the United States and 10 rigs in Canada. For the three months ended December 2009, the Company had an average of 103 drilling rigs operating, including 95 rigs in the United States and 8 rigs in Canada.

Average drilling rigs operating reported in the Company's monthly announcements represent the average number of the Company's drilling rigs that were operating under a drilling contract. The Company cautioned that numerous factors in addition to average drilling rigs operating can impact the Company's operating results and that a particular trend in the number of drilling rigs operating may or may not indicate a trend in or be indicative of the Company's financial performance. The Company intends to continue providing monthly updates on drilling rigs operating shortly after the end of each month.

About Patterson-UTI

Patterson-UTI Energy, Inc. provides onshore contract drilling services to exploration and production companies in North America. The Company has approximately 350 marketable land-based drilling rigs that operate primarily in the oil and natural gas producing regions of Texas, New Mexico, Oklahoma, Arkansas, Louisiana, Mississippi, Alabama, Colorado, Arizona, Utah, Wyoming, Montana, North Dakota, South Dakota, Pennsylvania, West Virginia and western Canada. Patterson-UTI Energy, Inc. is also engaged in the businesses of pressure pumping services and drilling and completion fluid services.

Statements made in this press release which state the Company's or management's intentions, beliefs, expectations or predictions for the future are forward-looking statements. It is important to note that actual results could differ materially from those discussed in such forward-looking statements. Important factors that could cause actual results to differ materially include, but are not limited to, deterioration in the global economic environment, declines in oil and natural gas prices that could adversely affect demand for the Company's services, and their associated effect on day rates, rig utilization and planned capital expenditures, excess availability of land drilling rigs, including as a result of the reactivation or construction of new land drilling rigs, adverse industry conditions, difficulty in integrating acquisitions, demand for oil and natural gas, shortages of rig equipment and ability to retain management and field personnel. Additional information concerning factors that could cause actual results to differ materially from those in the forward-looking statements is contained from time to time in the Company's SEC filings, which may be obtained by contacting the Company or the SEC.