Calypso Signs Definitive Option Agreement for a Joint Venture on the Majority of Calypso's Argentine Uranium Properties

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Sept. 21, 2010) - CALYPSO URANIUM CORP. (TSX VENTURE:CLP) ("Calypso" or the "Company") is pleased to announce the Company has signed an Option Agreement (the "Agreement") with Cameco Global Exploration Ltd. ("Cameco Global"), a wholly-owned subsidiary of Cameco Corporation ("Cameco"), to explore and develop Calypso's uranium projects in Argentina with the exception of the Huemul property in the Province of Mendoza which will be retained by Calypso. The Agreement will be completed through an equity investment by Cameco Global in Calypso's wholly-owned subsidiary Energia Mineral Inc. ("Energia Mineral"). The Agreement was signed on September 21, 2010, following the Letter of Intent announced in the Company's news release of April 13, 2010.

Under the terms of the Agreement, Calypso has granted Cameco Global the option to acquire a 51% interest in Energia Mineral by Cameco Global investing a total of C$9,000,000 in Energia Mineral's Argentine uranium properties, over a maximum three-year period. During the first year of the Agreement, Cameco Global has committed to fund C$3,000,000 of Energia Mineral's agreed exploration and development programs. The decision to proceed with a further $3,000,000 in exploration in years two and three is at Cameco Global's discretion.

The Energia Mineral project areas included in the Agreement cover approximately 442,542 hectares and include the La Pintada, Ranquil Co, Central Block, Campesino Norte and San Jorge Basin projects.

"We are excited to have Cameco, a recognized uranium industry leader as our partner in our exploration activities in Argentina. Their extensive experience in all aspects of exploration, development and production will significantly strengthen the development of our projects over the medium and long term," said Stephen Barley, President of Calypso.

Under the terms of the Agreement, Energia Mineral will continue to lead exploration activities during the option period based on exploration proposals approved by a joint technical committee. In the event Cameco Global exercises its option and acquires a 51% interest in Energia Mineral, Cameco Global has the right but not the obligation to become the operator.

Guillermo Pensado, Vice President Exploration of Calypso and President of Energia Mineral, said, "The signing of this agreement is a testament to the quality of the properties the Company has assembled in areas of Argentina with high uranium potential, and we look forward to working with Cameco through the joint technical committee to deliver the agreed exploration program."

About Cameco

Cameco, with its head office in Saskatoon, Saskatchewan, Canada, is one of the world's largest uranium producers. The company's uranium products are used to generate electricity in nuclear energy plants around the world, providing one of the cleanest sources of energy available today. Cameco's shares trade on the Toronto and New York stock exchanges.

About Calypso

Calypso Uranium Corp. is a mineral exploration company whose principal focus is the exploration and development of uranium properties in Argentina and in the United States. Calypso is active in Argentina with more than 470,257 hectares or 4,702km2 of claims and mineral concessions in the provinces of Chubut, Mendoza and Neuquen. Through the Argentine branch of its subsidiary Energia Mineral Inc., the Company has an exploration office located in Mendoza working closely with local communities while operating to the highest national and international safety and environmental standards. To promote transparency and to build awareness and public understanding of uranium exploration, all of Calypso's environmental impact reports and its "Radiological Safety and Protection Guide for Uranium Exploration" are posted on its website. While maintaining its principal focus on the development of the Argentine uranium projects, Calypso has a 50% interest and is operator of the Sage Creek properties located in Converse County, Wyoming. Calypso is well-funded to advance all exploration projects and has the technical team and management structure for this effort. Further information is available at the website, www.calypsouranium.com, or filed under the Company's profile at www.sedar.com.

CALYPSO URANIUM CORP.

Stephen Barley, President & CEO

This news release may contain forward-looking statements based on assumptions and judgments of management of the Company regarding future events or results. Such statements are subject to a variety of risks and uncertainties which could cause actual events or results to differ materially from those reflected in the forward-looking statements. The Company disclaims any intention or obligation to revise or update such statements except as may be required by law.

Shares Outstanding: 50,630,819

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

For more information, please contact
Calypso Uranium Corp.
Investor Relations
1-604-639-4671
info@calypsouranium.com
www.calypsouranium.com

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