Osisko Intercepts 68 Metres Averaging 1.26 g/t Au, 31.5 g/t Ag, 0.5% Cu at Cuervo

MONTREAL, QUEBEC--(Marketwired - July 4, 2013) - Osisko Mining Corporation (the "Company" or "Osisko") (TSX:OSK)(FRANKFURT:EWX) is pleased to present initial results from its greenfields exploration activities in the Guerrero Gold Belt, Mexico.

Highlights:

• Osisko has identified 6 main anomalies which are at or near drill stage, including the Milagro Anomaly, which has a 4 km x 1 km soil and lithogeochemical signature
• 114 targets remain to be reviewed
• 11,870 km² of Au prospective geology has been covered with approximately 7,700 stream sediment samples as well as 2,800 rock and 3,800 soil samples
• Geophysics completed over 320 km²
• Osisko presently controls 9,600 km² of mineral rights in Mexico

Cuervo Anomaly

Drilling at Cuervo indicates the presence of Au-Ag-Cu skarn mineralization within a 4km x 2 km corridor. Twenty reconnaissance drill holes were completed in the anomalous area defined by rock and soil geochemistry. Drill results detailed below show significant mineralized intercepts. Subsequent to the preliminary exploratory drilling, mapping and sampling has extended the defined mineralization along strike. Follow-up work on these extensions is planned.

Milagro Anomaly

The largest anomaly identified by the stream sediment sampling program is Milagro, where skarn and epithermal mineralization are developed within a 20 km x 10 km area of hydrothermal alteration.

The main target within Milagro is defined by a 4 km x 1 km soil and rock anomaly produced by discontinuous outcrops of gossans developed after the oxidation of magnetite-sulphide bearing skarn. Gold in soil values within this anomalous corridor vary between 50 and 4,800 ppb Au and 0.05% Cu to 1.23% Cu, with a higher grade area of 1 km x 1.2 km with continuous rock values ranging between 500 and 4,800 ppb Au and 0.1% to 1.23% Cu. Rock samples from the discontinuous gossans outcrops present gold values between 50 ppb and 8.2 g/t, with more than 25% of samples with gold values higher than 0.5 g/t. The main target is open to the north, is drill ready and all necessary permits are expected to be received in the second half of 2013.

An additional three target areas are in detailed mapping and sampling phase. Reconnaissance sampling and mapping over the entire Milagro altered area is in progress and additional drill targets are expected to be developed.

A map of the Milagro Anomaly Au Soil Geochemistry is available at the following address: http://media3.marketwire.com/docs/130704_OSK-Milagro_Anomaly.pdf.

Quality Control

True widths of reported intervals are interpreted based on drill-hole intercepts and interpreted orientations of intersected lithologies and are estimated at 85-90% of the core length interval. Assays are uncut. All HQ core assays reported were obtained by standard 30 g fire-assaying-AA finish at ALS-Chemex Laboratories of Vancouver, BC. Drill program design, Quality Assurance/Quality Control and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards and blanks are submitted every 25 samples for QA/QC purposes by the Company as well as the lab. Approximately 5% of sample rejects and/or pulps are sent to secondary laboratories for check assaying.

Mr. Robert Wares, P.Geo. Chief Geologist of Osisko Mining Corporation is the Qualified Person who has reviewed this news release and is responsible for the technical information reported herein, including verification of the data disclosed.

About Osisko Mining Corporation

Osisko Mining Corporation operates the Canadian Malartic Gold mine in Malartic, Québec and is carrying out exploration and project development within the Americas.

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, obtaining favourable results from our exploration activities in Mexico. 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 exploration work in Mexico, 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, results of exploration and development activities, uninsured risks, regulatory changes, defects in title, availability of personnel, materials and equipment, timeliness of government approvals, 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.