20 December 2006

Gran Tierra Awarded Second Block in Peru; Establishes Dominant Position in Iquitos Arch Trend

CALGARY, Alberta, December 20, 2006 – Gran Tierra Energy Inc. (OTC Bulletin Board: GTRE.OB) – On December 12, 2006, a License Contract for the Exploration and Exploitation of Hydrocarbons covering Block 128 in Peru between Gran Tierra Energy Peru and PeruPetro S.A. was signed and ratified by Supreme Decree, and is now effective. With a 100% working interest, Gran Tierra Energy is operator of the block.

Block 128 is adjacent to Gran Tierra’s existing acreage in Block 122, which was awarded to the Company earlier in 2006. The two blocks are located on the eastern flank of the Mara~non Basin in northern Peru, on the crest of the Iquitos Arch. Block 128 covers 2.2 million acres. Together with Block 122, the Company now has a 100% working interest in 3.2 million acres over the Iquitos Arch, the largest landholding on this trend.

The License Contract for Block 128 defines a seven-year exploration term divided into four periods, each involving a minimum work/financial commitment. The minimum commitment for the first work period, which is mandatory, is $0.5 million. The potential commitment over the seven-year period is $3.6 million and includes technical studies, seismic acquisition and the drilling of one exploration well. The License Contract defines an exploitation term of thirty years for commercial discoveries of oil.

Dana Coffield, President and Chief Executive Officer of Gran Tierra, stated, “This second transaction marks the completion of our exploration land acquisition in a significant new exploration play in Peru. We now have the dominant acreage position in this play, and will begin work in 2007 towards maturing this land to define seismic acquisition programs and future drilling opportunities.”

About Gran Tierra Energy Inc.

Gran Tierra Energy, Inc. is an international oil and gas exploration and production company, headquartered in Calgary, Canada, incorporated and traded in the United States and operating in South America. The Company holds interests in producing and prospective properties in Argentina, Colombia and Peru. To date, the Company has pursued a strategy that focuses on establishing a portfolio of producing properties, development and exploration opportunities, through selective acquisitions, to provide a base for future growth. Additional information concerning Gran Tierra is available at www.grantierra.com. Investor inquiries may be directed to info@grantierra.com or 1-800-916-GTRE (4873).

Forward Looking Statements

This press release contains ‘forward-looking statements’ within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, including without limitation those statements regarding the Company’s ability to exploit oil and gas exploration opportunities. These statements are expressed in good faith and based upon a reasonable basis when made, but there can be no assurance that these expectations will be achieved or accomplished. Although the forward-looking statements in this release reflect the good faith judgment of management, forward-looking statements are inherently subject to known and unknown risks and uncertainties that may cause actual results to be materially different from those discussed in these forward-looking statements including, but not limited to, our ability to complete the Company’s drilling program for 2007, our ability to discover reserves that may be extracted on a commercially viable basis, difficulties inherent in estimating oil and gas reserves, intense competition in the oil and gas industry, environmental risks, regulatory changes and general economic conditions including the price of oil and gas. Readers are urged not to place undue reliance on these forward-looking statements, which speak only as of the date of this release. We assume no obligation to update any forward-looking statements in order to reflect any event or circumstance that may arise after the date of this release, other than as may be required by applicable law or regulation. Readers are urged to carefully review and consider the various disclosures made by us in the our reports filed with the Securities and Exchange Commission, including those risks set forth in the Company’s Annual Report on Form 10-KSB filed on March 10, 2006, as amended, which attempt to advise interested parties of the risks and factors that may affect our business, financial condition, results of operation and cash flows. If one or more of these risks or uncertainties materialize, or if the underlying assumptions prove incorrect, our actual results may vary materially from those expected or projected. We undertake no obligation to update these forward looking statements.