Atlas Energy Resources, LLC Prices Public Offering of Common Units

Atlas Energy Resources, LLC (NYSE: ATN) ("Atlas Energy") announces today that Atlas Energy has priced a public offering of 1.6 million common units representing Class B limited liability company interests. UBS Investment Bank and Wachovia Securities acted as joint book-running managers and underwriters of this offering. The underwriters have been granted an option to purchase up to an additional 240,000 common units. In addition, Atlas Energy will concurrently sell 600,000 common units to Atlas America, Inc. (NASDAQ: ATLS) in a private placement, increasing Atlas America's ownership of Atlas Energy's common units to 29,952,996 common units. Atlas Energy intends to use the net proceeds from these offerings to repay a portion of its outstanding balance under its revolving credit facility to create additional borrowing capacity to fund additional acreage acquisitions and accelerated development of the Marcellus Shale as well as further development of its other drilling programs and lease acquisition activities.

This press release does not constitute an offer to sell or a solicitation of an offer to buy any securities. The offer is being made only through the prospectus supplement and accompanying base prospectus, which is part of a registration statement that became effective on March 13, 2008. The common units that are being sold in the private placement have not been registered under the Securities Act of 1933, as amended, and may not be sold in the United States absent registration or an applicable exemption from registration requirements.

When available, a copy of the prospectus supplement and accompanying base prospectus relating to the public offering may be obtained from the underwriters as follows:

UBS Investment Bank
Attention: Prospectus Department
299 Park Avenue
New York, NY 10171
Toll free: 888-827-7275

Wachovia Securities
Equity Syndicate Department
375 Park Avenue
New York, NY 10152
Email:  equity.syndicate@wachovia.com

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 Appalachian Basin and northern Michigan. Atlas Energy sponsors and manages tax-advantaged investment partnerships, in which it co-invests, to finance the exploration and development of the Company's acreage in the Appalachian Basin. Atlas Energy is active principally in Pennsylvania, Michigan and Tennessee. For more information, visit Atlas Energy's website at www.atlasenergyresources.com or contact Investor Relations at bbegley@atlasamerica.com .

Certain matters discussed within this press release are forward-looking statements. Although Atlas Energy Resources, LLC believes the expectations reflected in such forward-looking statements are based on reasonable assumptions, it can give no assurance that its expectations will be attained. Factors that could cause actual results to differ materially from expectations include financial performance, regulatory changes, changes in local or national economic conditions and other risks detailed from time to time in Atlas Energy's reports filed with the SEC, including quarterly reports on Form 10-Q, reports on Form 8-K and annual reports on Form 10-K.