Osisko Exercises Buy Out Option in Canadian Malartic Net Smelter Royalty

MONTREAL, QUEBEC--(Marketwire - March 28, 2011) - Osisko Mining Corporation ("Osisko")(TSX:OSK)(FRANKFURT:EWX) is pleased to report that it has exercised its buy out option to purchase 50% of the net smelter royalty held over certain claims included in the Canadian Malartic property for US$1.5 million.

Subsequent to the buy-out and upon the commencement of production at Canadian Malartic, the Company will pay a net smelter royalty of 1.5% originating from certain claims when the price of gold is equal to or above US$350 per ounce, and 1% when the price of gold is below US$350 per ounce to Royal Gold Inc., the current royalty owner.

Mr. Sean Roosen, President and CEO, commenting on the transaction said: "This exercise of the buy-out option is another milestone in our pursuit of placing the Canadian Malartic Project into production. With the steady and on-going progress in plant commissioning, we anticipate achieving commercial production in May 2011."

Forward-Looking Statements

Certain statements contained in this press release may be deemed "forward-looking statements". All statements in this release, other than statements of historical fact, that address events or developments that Osisko expects to occur, are forward looking statements. Forward looking statements are statements that are not historical facts and are generally, but not always, identified by the words "expects", "plans", "anticipates", "believes", "intends", "estimates", "projects", "potential", "scheduled" and similar expressions, or that events or conditions "will", "would", "may", "could" or "should" occur including, without limitation, the commencement of commercial production. Although Osisko believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, including, without limitation, that all technical, economical and financial conditions will be met in order to warrant further development of the project, such statements are not guarantees of future performance and actual results may differ materially from those in forward looking statements. Factors that could cause the actual results to differ materially from those in forward-looking statements include gold prices, access to skilled consultants, mining development personnel, results of exploration and development activities, Osisko's limited experience with production and development stage mining operations, uninsured risks, regulatory changes, defects in title, availability of personnel, materials and equipment, timeliness of government approvals, actual performance of facilities, equipment and processes relative to specifications and expectations, unanticipated environmental impacts on operations market prices, continued availability of capital and financing and general economic, market or business conditions. These factors are discussed in greater detail in Osisko's most recent Annual Information Form and in the most recent Management Discussion and Analysis filed on SEDAR, which also provide additional general assumptions in connection with these statements. Osisko cautions that the foregoing list of important factors is not exhaustive. Investors and others who base themselves on forward-looking statements should carefully consider the above factors as well as the uncertainties they represent and the risk they entail. Osisko believes that the expectations reflected in those forward-looking statements are reasonable, but no assurance can be given that these expectations will prove to be correct and such forward-looking statements included in this press release should not be unduly relied upon. These statements speak only as of the date of this press release.