18 Marzo 2011

Gran Tierra Energy Announces the Successful Closing of Petrolifera Acquisition

Acquisition Adds Substantial Underdeveloped Assets to Portfolio in Colombia, Peru and Argentina

CALGARY, Alberta, March 18, 2011, Gran Tierra Energy Inc. (NYSE AMEX: GTE; TSX: GTE) (“Gran Tierra Energy”)a company focused on oil and gas exploration and production in South America, is pleased to announce the successful completion of its acquisition of all the issued and outstanding common shares and warrants of Petrolifera Petroleum Limited (“Petrolifera”) by way of statutory plan of arrangement (the “Arrangement”). Under the Arrangement, Petrolifera shareholders received, for each Petrolifera share held, 0.1241 of a share of Gran Tierra Energy common stock, and Petrolifera warrant holders received, for each Petrolifera warrant held, 0.1241 of a warrant to purchase a share of Gran Tierra Energy common stock at an exercise price of $9.67 per share. The Gran Tierra Energy warrants expire on August 28, 2011.

The Arrangement was approved at a special meeting of Petrolifera shareholders on March 17, 2011 and by the Court of Queen’s Bench of Alberta on March 18, 2011. Approximately 72% of the Petrolifera shareholders voted, with over 99% of the votes cast by Petrolifera shareholders voting in favor of the Arrangement. Gran Tierra Energy has acquired all the issued and outstanding Petrolifera shares and warrants through the issuance of approximately 18.2 million Gran Tierra Energy shares and approximately 4.1 million Gran Tierra Energy warrants.

“The successful closing of this transaction represents a milestone for Gran Tierra Energy as we have now added substantially to our asset base in Colombia, Peru and Argentina,” said Dana Coffield, President and Chief Executive Officer of Gran Tierra Energy. “The acquisition adds undeveloped oil and gas reserve potential in Colombia, exploration opportunities in Colombia and Peru and additional oil production and reserves in a rising oil price environment in Argentina. Gran Tierra Energy has retained its strong balance sheet and cash position to further develop the assets acquired in this transaction.”

Petrolifera shares and warrants are expected to be de-listed from the Toronto Stock Exchange (“TSX”) in due course when the TSX confirms receipt of all necessary documents in connection with the closing of the Arrangement and related matters. 

Gran Tierra Energy expects to announce a revised 2011 work program and budget shortly once final internal approvals are obtained.

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 NYSE Amex (GTE) and the Toronto Stock Exchange (GTE), and operating in South America. Gran Tierra Energy holds interests in producing and prospective properties in Argentina, Colombia, Peru and, subject to regulatory approval, Brazil. Gran Tierra Energy 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.

Gran Tierra Energy’s Securities and Exchange Commission filings are available on a web site maintained by the Securities and Exchange Commission at http://www.sec.gov and on SEDAR at http://www.sedar.com.

Forward Looking Statements:

This news release contains certain forward-looking information and forward-looking statements (collectively, “forward-looking statements”) under the meaning of applicable securities laws, including Canadian Securities Administrators’ National Instrument 51-102 – Continuous Disclosure Obligations and the United States Private Securities Litigation Reform Act of 1995. The use of the words “expect”, “anticipate”, “may” and “will” and similar terms identify these forward-looking statements. In particular, but without limiting the foregoing, this news release contains forward-looking statements regarding the de-listing of the Petrolifera shares and warrants from the TSX and the announcement of a revised 2011 work program and budget. The forward-looking statements contained in this news release reflect several material factors and expectations and assumptions of Gran Tierra Energy which Gran Tierra Energy believes are reasonable at this time but no assurance can be given that these factors, expectations and assumptions will prove to be correct.

The forward-looking statements contained in this news release are subject to risks, uncertainties and other factors that could cause actual results or outcomes to differ materially from those contemplated by the forward-looking statements, including, among others, that in the event that Gran Tierra Energy is unable to meet the TSX requirements for de-listing in the timeframe currently anticipated, the de-listing of the Petrolifera common shares and warrants may be delayed; and in the event that Gran Tierra Energy is unable to assess the information required to revise the 2011 work program and budget within the currently anticipated timeframe, the announcement of a revised 2011 work program and budget may be delayed indefinitely. The forward-looking statements contained herein are expressly qualified in their entirety by this cautionary statement. The forward-looking statements included in this press release are made as of the date of this press release and Gran Tierra Energy disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as expressly required by applicable securities legislation.

Contact Information

For investor and media inquiries please contact:

Jason Crumley

Director, Investor Relations