Exhibit 99.1

News Release

For Immediate Release 04/19/10

ATP Oil & Gas Corporation, Houston

Chairman and CEO

T. Paul Bulmahn, 713-622-3311

or

Chief Financial Officer

Albert L. Reese Jr., 713-622-3311

www.atpog.com

ATP Prices Private Offering of $1.5 Billion 11.875% Senior Second Lien Notes Due 2015

HOUSTON – April 19, 2010 – (Business Wire) –ATP Oil & Gas Corporation (NASDAQ: ATPG) today announced that it has priced a private offering of $1.5 billion aggregate principal amount of senior second lien notes due 2015 (“Notes”). The Notes will have an interest rate of 11.875% per annum and will be issued at a price of 99.531% of their face value. The Notes offering is expected to close on April 23, 2010, subject to customary closing conditions. ATP will use the net proceeds of the Notes to repay its existing senior secured term loans in full, to pay associated fees and expenses and for general corporate purposes. Concurrently with the closing of the offering, ATP will enter into a new $100 million senior secured revolving credit facility.

The Notes will not be registered under the Securities Act of 1933 or the securities laws of any state and may not be offered or sold in the United States absent registration or an applicable exemption from the registration requirements under the Securities Act and applicable state securities laws. The Notes may be resold by the initial purchasers pursuant to Rule 144A and Regulation S under the Securities Act. This press release is being issued pursuant to Rule 135c under the Securities Act of 1933. This press release shall not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale of these securities in any state in which the offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state.

About ATP Oil & Gas Corporation

ATP Oil & Gas is focused on development and production of oil and natural gas in the Gulf of Mexico and the 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 are “forward-looking statements” under the Private Securities Litigation Reform Act of 1995. ATP cautions that assumptions, expectations, projections, intentions, or beliefs about future events may, and often do, vary from actual results and the differences can be material. Some of the key factors which could cause actual results to vary from those ATP expects include changes in natural gas and oil prices, the timing of planned capital expenditures, availability of acquisitions, uncertainties in estimating proved

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 our ability to access them, and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments affecting our business. The SEC has generally permitted oil and gas companies, in filings made with the SEC, to disclose only proved reserves that a company has demonstrated by actual production or conclusive formation tests to be economically and legally producible under existing economic and operating conditions. We and our independent third party reservoir engineers use the terms “probable” and “possible” and we use the term “recoverable hydrocarbons” to describe volumes of reserves potentially recoverable through additional drilling or recovery techniques that the SEC’s guidelines may prohibit us from including in filings with the SEC. These estimates are by their nature more speculative than estimates of proved reserves. All estimates of probable and possible reserves in this news release have been prepared by our independent third party engineers and all estimates of recoverable hydrocarbons have been prepared by management. More information about the risks and uncertainties relating to ATP’s forward-looking statements is found in our SEC filings.

###