Patterson-UTI Announces Internal Investigation

Patterson-UTI Energy reports that as a result of information received by senior management of the Company on November 9, 2005, the Audit Committee of the Board of Directors of the Company has begun an investigation into unauthorized payments made by the Company for assets which were not delivered to the Company. The Audit Committee will engage legal counsel and forensic accountants to conduct the investigation. Based on preliminary findings, it appears that approximately $70 million may have been embezzled from the Company by a former officer over a period of more than five years. Because the investigation is just beginning the Company has not yet made a final determination as to the impact of these developments upon its previous financial results and assessment of internal controls.

The Company has advised the Securities and Exchange Commission of this matter and is in the process of advising appropriate criminal enforcement agencies. The Company intends to cooperate fully with these governmental authorities.