CALGARY, Alberta (Map) - CALGARY, Alberta, May 9 /PRNewswire-FirstCall/ -- Gran Tierra Energy Inc. (TSX: GTE; Amex: GTE), a company focused on oil exploration and production in South America, announced today that it will restate the company's financial statements for previously reported quarters ended March 31, 2007, June 30, 2007 and September 30, 2007 and the years ended December 31, 2007 and 2006. The company discovered a misclassification of accounts payable and accrued liabilities resulting in a misstatement of cash flows from operating activities, with a corresponding offset to cash flows from investing activities. The restatement will have no effect on the previously reported net change in cash and cash equivalents and no impact on previously reported consolidated balance sheets or consolidated statements of operations and accumulated deficit. The company will file an amendment to its annual report on Form 10-K for the year ended December 31, 2007 to reflect the restatement.

In the course of preparing its interim financial statements for its quarterly report on Form 10-Q to be filed with the Securities and Exchange Commission for the quarter ended March 31, 2008, the company discovered the misclassification in its 2007 interim financial statements for the previously reported quarters ended March 31, 2007, June 30, 2007 and September 30, 2007, and annual financial statements for the years ended December 31, 2007 and 2006. The company is in the process of completing its assessment of this matter.

As a result, management and the audit committee have concluded that the company's previously-filed financial statements for the corresponding periods should not be relied upon. The company plans to file its Form 10-K/A containing its restated 2007 and 2006 financial statements, and reflecting the corrections to the financial statements for the interim periods in 2007, on Monday, May 12, 2008.

About Gran Tierra Energy Inc.:

Gran Tierra Energy Inc. is an international oil and gas exploration and production company, headquartered in Calgary, Canada, incorporated in the United States, trading on the Toronto Stock Exchange (GTE) and the American Stock Exchange (GTE), and operating in South America. The company holds interests in producing and prospective properties in Argentina, Colombia and Peru. The company has a strategy that focuses on establishing a portfolio of producing properties, plus production enhancement and exploration opportunities to provide a base for future growth. Additional information concerning Gran Tierra Energy is available at http://www.grantierra.com. Investor inquiries may be directed to info@grantierra.com or 1-800-916-GTRE (4873).

Forward Looking Statements:

The statement in this news release regarding the company's expected filing of its Form 10-K/A on May 12, 2008 is a "forward-looking statement" that is subject to risks, uncertainties and other factors that could cause a delay in the filing of the Form 10-K/A. There are a number of important factors that could cause a delay in the filing of the Form 10-K/A, including the required reviews of the Form 10-K/A by outside auditors and consultants may take more time than expected, and Gran Tierra Energy may not be able to obtain all required consents to the filing by such date. Gran Tierra Energy does not undertake an obligation to update the forward-looking statement in this release.