19 Marzo 2007

Gran Tierra Preparing To Test Exploration Well In Colombia

Oil Shows Encountered In Four Zones

CALGARY, Alberta, March 19, 2007, Gran Tierra Energy Inc. (OTCBB: GTRE.OB) today announced that it has successfully drilled and logged a new field wildcat well in the Guayuyaco Block, Putumayo Basin, in southern Colombia. Gran Tierra Energy holds a 50% working interest and is Operator of this block. Partner, Solana Resources Limited, holds a 50% working interest and Ecopetrol has a 30% interest back-in right on commercial discoveries. If Ecopetrol exercises its back-in right, then Gran Tierra Energy will hold a 35% working interest and retain Operatorship, and Solana Resources Limited will hold a 35% working interest in the new commercial field. Gran Tierra reported that its Juanambu-1 well reached a total measured depth of 9,154 feet on March 10, 2007. The well encountered reservoir quality sandstones with hydrocarbon shows in four zones. Initial log interpretations indicate potential oil pay in the T Sandstone Unit of the Villeta Formation and in the Caballos Formation. There is additional potential oil pay in the Kg Sand Unit of the Rumiyaco Formation and in the U Sandstone Unit of the Villeta Formation, subject to confirmation by planned well testing. The four reservoirs encountered are proven producing reservoirs in oil fields in the adjacent Santana Block operated by Gran Tierra. The Juanambu-1 well bore is currently being cased. A service rig with test equipment will move to the Juanambu-1 location to run a completion string and initiate testing of the hydrocarbon zones in early April.

The Pride-17 drilling rig will be mobilized to the adjoining Chaza Block to drill the Costayaco-1 exploration well once the Juanambu-1 well bore is cased. Gran Tierra currently expects drilling of Costayaco-1 to commence in early April. Gran Tierra is the operator of the Chaza block with a 50% working interest.

Dana Coffield, President and Chief Executive Officer of Gran Tierra, stated “These early positive evaluation results justify an extensive testing program to evaluate the commercial potential of the encountered hydrocarbons zones. The results of this testing activity will be particularly interesting to us as the Juanambu structure is in close proximity to adjacent land and infrastructure operated by Gran Tierra Energy.”

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

The statement in this press release regarding the timing of the commencement of drilling of the Costayaco-1 exploration well in early April is a ‘forward-looking statement’ within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934. This statement is expressed in good faith and based upon a reasonable basis when made, but there can be no assurance that this expectation will be achieved or accomplished. Although this forward-looking statement reflects 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, mechanical problems and delays in preparation of the drill site. Readers are urged not to place undue reliance on this forward-looking statement, which speak only as of the date of this release. Gran Tierra assumes no obligation to update this forward-looking statement 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 Gran Tierra in its reports filed with the Securities and Exchange Commission, including those risks set forth in the Gran Tierra’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 Gran Tierra’s 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, Gran Tierra’s actual results may vary materially from those expected or projected. Gran Tierra undertakes no obligation to update forward looking statements.