Atlas Energy Resources, LLC Announces Tommy L. Thompson as Vice President of Horizontal Drilling.

PITTSBURGH -- Atlas Energy Resources, LLC (NYSE: ATN) ("Atlas Energy") announced today the appointment of Tommy L. Thompson to the position of Vice President, Horizontal Drilling. Mr. Thompson's primary responsibilities will include the oversight of Atlas Energy's horizontal drilling efforts, particularly in the Marcellus Shale in southwestern Pennsylvania.

Mr. Thompson comes to Atlas Energy with 30 years of experience in drilling engineering, including horizontal and extended reach drilling. Most recently, Mr. Thompson was with Wagner & Brown, where he managed the vertical and horizontal drilling operations in the Woodford Shale in eastern Oklahoma. Prior to Wagner & Brown, Mr. Thompson worked for Occidental Petroleum for over 28 years, where he eventually led drilling operations in the Permian Basin of western Texas, Ecuador and Qatar. Mr. Thompson has a Bachelor of Science degree in Petroleum Engineering from Louisiana Tech University.

"We are thrilled that Tommy has joined Atlas as a senior member of our operating team," stated Richard D. Weber, President and Chief Operating Officer of Atlas Energy. "He is a proven manager of large scale horizontal drilling programs and is the perfect complement to our already deep bench of talent. Tommy is already making contributions, most notably in our horizontal development of the Marcellus Shale."

Atlas Energy Resources, LLC develops and produces domestic natural gas and to a lesser extent, oil. Atlas Energy is one of the largest independent energy producers in the Eastern United States. Atlas Energy sponsors and manages tax-advantaged investment partnerships, in which it co-invests, to finance the development of its acreage. For more information, visit Atlas Energy's website at www.atlasenergyresources.com or contact Investor Relations at [e-mail].