ATP Declares Cash Dividend on Preferred Stock

ATP Oil & Gas Corporation (NASDAQ: ATPG) announced that its Board of Directors declared quarterly cash dividends on its 8.0% Cumulative Convertible Perpetual Preferred Stock. The dividend rate for the September 2009 series is $2.02 per share and is payable on January 3, 2012 to shareholders of record at the close of business on December 15, 2011. The dividend rate for Series B issued June 2011 is $2.02 per share and is payable on January 3, 2012 to shareholders of record at the close of business on December 15, 2011.

About ATP Oil & Gas Corporation

ATP Oil & Gas is an international offshore oil and gas development and production company focused in the Gulf of Mexico, Mediterranean Sea and North Sea. The company trades publicly as ATPG on the NASDAQ Global Select Market. For more information about ATP Oil & Gas Corporation, visit www.atpog.com.

Forward-looking Statements

Certain statements included in this news release contain "forward-looking statements" within the meaning of the "safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934. ATP cautions that assumptions, expectations, projections, intentions, plans, beliefs or similar expressions used to identify forward-looking statements about future events may, and often do, vary from actual results and the differences can be material from those expressed or implied in such forward looking statements. Some of the key factors which could cause actual results to vary from those ATP expects include, without limitation, volatility in commodity prices for crude oil and natural gas, the timing of planned capital expenditures, availability of acquisitions, uncertainties in estimating reserves and forecasting production results, operational factors affecting the commencement or maintenance of producing wells, the condition of the capital markets generally, as well as ability to access them, and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments affecting its business. ATP assumes no obligation and expressly disclaims any duty to update the information contained herein except as required by law. More information about the risks and uncertainties relating to ATP's forward-looking statements is found in the company's SEC filings or website, www.atpog.com.