OSISKO INTERSECTS 97.6 g/t Au OVER 3.3 METRES AT LYNX

Infill Drilling Continues to Encounter High-Grade Gold

(Toronto, June 7, 2018)  Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new results from the ongoing drill program at its 100% owned Windfall Lake gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec. The 800,000 metre drill program commenced in late 2015 is now focussed on infill drilling within the main Windfall gold deposit and the adjacent Lynx deposit (located immediately NE of Windfall).  Exploration and expansion drilling is also continuing at Windfall with several deep holes in progress to investigate the down-plunge areas in and around the Underdog and Lynx zones.

Today’s results include significant new analytical results from 49 intercepts in 28 drill holes and 2 wedges focused on infill drilling in the Lynx deposit.

Highlights from the new results include: 97.6 g/t Au over 3.3 metres in OSK-W-18-1511; 79.1 g/t Au over 2.7 metres in OSK-W-18-909-W5; 74.3g/t Au over 2.6 metres in OSK-W-18-1536; 64.2 g/t Au over 3.0 metres in OSK-W-18-1470; 42.8 g/t Au over 2.3 metres in OSK-W-17-1098; 20.1 g/t Au over 3.7 metres in OSK-W-18-1477; and 14.5 g/t Au over 4.7 metres in OSK-W-18-1496. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Notes:  True widths are estimated at 65 – 80% of the reported core length interval.  See “Quality Control and Reporting Protocols” below.

Definition: VNCR = Crustiform Vein.

OSK-W-17-979 intersected 17.0 g/t Au over 2.0 metres and 3.22 g/t Au over 2.2 metres.  Mineralization contains trace disseminated and stringer pyrite hosted in a moderate sericite and weak silica altered rhyolite and porphyritic felsic dike.

OSK-W-17-1098 intersected 42.8 g/t Au over 2.3 metres. Mineralization contains up to 7% pyrite-tourmaline stringers and trace pyrite clusters in a locally silicified and sericitized gabbro near the contact with fragmental felsic dike.

OSK-W-18-909-W5 intersected 79.1 g/t Au over 2.7 metres. Mineralization contains up to 10% pyrite stringers, clusters and interstitial dissemination and 1% chalcopyrite in pervasive silica flooding. The host is a moderately sericitized and strongly silicified rhyolite.

OSK-W-18-923-W2 intersected 6.80 g/t Au over 2.2 metres. Mineralization contains 1% disseminated pyrite and 1% pyrite clusters with 30% quartz veins within a moderately sericitized and locally silicified rhyolite.

OSK-W-18-1424 intersected 7.58 g/t Au over 2.2 metres. Mineralization contains 3% disseminated pyrite within a sheared, sericitized, chloritized and silicified andesite 50 metres from the Bank Fault.

OSK-W-18-1432 intersected 8.94 g/t Au over 2.0 metres. Mineralization contains 2% disseminated pyrite and clusters within a moderate sericite and weak silica altered porphyritic felsic dike.

OSK-W-18-1436 intersected 10.1 g/t Au over 2.5 metres. Mineralization contains 1% disseminated pyrite and 2% pyrite-tourmaline stringers in a moderate chlorite and weak silica altered andesite.

OSK-W-18-1450 intersected 13.4 g/t Au over 2.0 metres. Mineralization contains 1% pyrite clusters and trace pyrite-tourmaline stringers in a small gabbroic dike with slight sericite and fuchsite alteration hosted in a rhyolite.

OSK-W-18-1462 intersected 3.77 g/t Au over 2.7 metres. Mineralization contains up to 15% pyrite with pervasive silica flooding within a sericitized and silicified rhyolite.

OSK-W-18-1464 intersected 4.75 g/t Au over 2.2 metres, 3.84 g/t Au over 2.9 metres, 8.07 g/t Au over 2.7 metres in Lynx and 3.80 g/t Au over 2.9 metres related to a crustiform vein. The first interval contains 5% pyrite clusters, 2% disseminated pyrite and trace pyrite stringers in a strongly sericitized and moderately chloritized rhyolite. The second interval contains 2% pyrite fragments and trace pyrite stringers in a strongly sericitized fragmental felsic dike. The third interval contains 5% disseminated pyrite and stringers with pervasive silica flooding hosted in a silicified fragmental dike. The last interval contains up to 5% disseminated pyrite and clusters, 5% pyrite-tourmaline stringers with a metre-scale crustiform and brecciated quartz-carbonate-fuchsite vein, hosted in a strongly carbonated and chloritized gabbro.

OSK-W-18-1470 intersected 14.5 g/t Au over 3.1 metres, 28.4 g/t Au over 2.0 metres, 5.43 g/t Au over 2.1 metres, and 64.2 g/t Au over 3.0 metres. The first interval contains 10% pyrite with pervasive silica flooding hosted in a rhyolite with weak fuschite alteration. The second interval contains 3% pyrite stringers with pervasive silica flooding and 1% pyrite fragments with a fragmental felsic dike. The third interval contains 10% pyrite with pervasive silica flooding in fragmental intrusive unit.  The fourth interval contains 2% pyrite in pervasive silica flooding and local visible gold hosted in a rhyolite in contact with a felsic intrusion.

OSK-W-18-1477 intersected 20.1 g/t Au over 3.70 metres. The interval is composed of a moderately sericitized, silicified and fuchsitized gabbro injected by 40% crustiform dismembered quartz-carbonates-tourmaline veins with 5% pyrite.

OSK-W-18-1483 intersected 3.31 g/t Au over 2.0 metres. Mineralization contains up to 2% pyrite with pervasive silica flooding and trace pyrite in quartz-tourmaline veins at a sericitized and weakly fuchsitized contact between a gabbro and a porphyritic felsic dike.

OSK-W-18-1486 intersected 3.60 g/t Au over 2.4 metres. Mineralization contains trace disseminated pyrite in a weakly sericitized and silicified rhyolite.

OSK-W-18-1492 intersected 10.1 g/t Au over 2.2 metres and 3.82 g/t Au over 2.4 metres related to crustiform veins.  Mineralization contains up to 2% pyrite in crustiform quartz-carbonate veins with local pervasive silica flooding, traces of pyrite within quartz-tourmaline veins and trace pyrite clusters. The host is a weakly fuchsitized and moderately chloritized andesite.

OSK-W-18-1495 intersected 7.54 g/t Au over 2.0 metres. Mineralization is composed of 3% pyrite stringers in a one metre-scale quartz-tourmaline vein hosted in a massive gabbro.

OSK-W-18-1496 intersected 14.5 g/t Au over 4.7 metres. Mineralization is composed of up 6% pyrite stringers with pervasive silica flooding hosted at the contact between a felsic fragmental dike and a rhyolite.

OSK-W-18-1501 intersected 20.8 g/t Au over 2.2 metres and 3.67 g/t Au over 2.0 metres. The first interval contains up to 6% disseminated pyrite and stringer with pervasive silica flooding within a sericitized and silicified porphyritic felsic dike. The second interval contains 8% disseminated pyrite at the contacts with quartz-carbonate veinlets with weak pervasive silica flooding in a bleached and strongly sericitized basalt.

OSK-W-18-1503 intersected 3.75 g/t Au over 2.0 metres. Mineralization contains 1% disseminated pyrite in a moderately sericitized rhyolite.

OSK-W-18-1511 intersected 97.6 g/t Au over 3.3 metres. Mineralization contains up to 1% pyrite stringers, 10% pyrite in pervasive silica flooding and local visible gold hosted in a silica and fuchsite altered fragmental rhyolite.

OSK-W-18-1512 intersected 3.38 g/t Au over 2.0 metres, 10.2 g/t Au over 2.4 metres, and 8.66 g/t Au over 2.0 metres in Lynx and 18.9 g/t Au over 2.8 metres related to a crustiform vein. The first interval contains 1% pyrite stringers and trace disseminated pyrite at a contact between a sericitized and silicified rhyolite and a foliated and chloritized gabbro. The second interval contains traces of disseminated pyrite in quartz clusters within a sericitized and bleached porphyritic felsic dike. The third interval contains up to 10% pyrite in pervasive silica flooding and folded quartz-carbonate veinlets hosted in a sericitized, silicified and bleached rhyolite. The fourth interval contains 10% disseminated and interstitial pyrite associated with crustiform veins hosted in a moderately sericitized, bleached, and fuchsite-altered gabbro.

OSK-W-18-1521 intersected 10.0 g/t Au over 2.0 metres. Mineralization contains up to 2% pyrite-tourmaline stringers with local visible gold within a silicified and sericitized fragmental felsic dike.

OSK-W-18-1523 intersected 8.24 g/t Au over 5.8 metres. Mineralization contains local visible gold in a dismembered quartz-carbonate vein and in crustiform veins, 3% disseminated and stringer pyrite, and 1% pyrite clusters hosted in a sericitized and locally chloritized andesite rhyolite.

OSK-W-18-1527 intersected 4.29 g/t Au over 2.0 metres and 12.5 g/t Au over 4.5 metres. The first interval contains up to 2% pyrite stringers and 2% disseminated pyrite in crustiform veins hosted at the contact between a bleached sericitized and silicified rhyolite and a bleached sericitized andesite. The second interval contains 5% pyrite and 2% sphalerite with pervasive silica flooding in a silicified and sericitized fragmental felsic dike with weak fuchsite alteration.

OSK-W-18-1529 intersected 7.16 g/t Au over 3.5 metres. Mineralization is related to quartz-carbonate-crustiform veins composed of 1% disseminated and stringer pyrite with silica-tourmaline-carbonate veins hosted in a chloritized gabbro.

OSK-W-18-1533 intersected 8.69 g/t Au over 2.4 metres. Mineralization contains local visible gold, 3% pyrite tourmaline stringers in crustiform veins, and 3% disseminated and stringer pyrite within a bleached and sericitized andesite.

OSK-W-18-1536 intersected 3.45 g/t Au over 2.1 metres, 74.3 g/t Au over 2.6 metres, 5.07 g/t Au over 2.2 metres, 3.39 g/t Au over 2.5 metres, 6.51 g/t Au over 3.0 metres, 3.43 g/t Au over 2.0 metres, and 3.59 g/t Au over 2.8 metres. The first interval contains trace disseminated pyrite, 3% pyrite-tourmaline stringers and quartz tourmaline veins in a sericitized rhyolite. The second, third and fourth intervals contain 5% disseminated pyrite and stringers at a contact between a sericitized and chloritized rhyolite with weak fuchsite alteration and a sericitized porphyritic felsic dike. The fifth interval is composed of trace disseminated pyrite in a sericitized rhyolite. The sixth interval is composed of 3% disseminated pyrite within a sericitized, silicified rhyolite near a contact with a gabbroic unit.

OSK-W-18-1539 intersected 3.75 g/t Au over 2.0 metres. Mineralization contains traces of disseminated pyrite and pyrite-tourmaline stringers in pervasive silica flooding within a sericitized and silicified rhyolite.

OSK-W-18-1540 intersected 6.43 g/t Au over 3.3 metres related to a crustiform vein. Mineralization contains up to 1% pyrite clusters and 3% pyrite stringers hosted in a moderately fuchsite altered gabbro with patchy silicification.

OSK-W-18-1550 intersected 10.3 g/t Au over 2.0 metres. Mineralization contains up to 6% disseminated and clustered pyrite hosted in a bleached gabbro injected by quartz-carbonate and quartz-tourmaline veins.

Qualified Person

The scientific and technical content of this news release has been reviewed, prepared and approved by Mr. Louis Grenier, M.Sc.A., P.Geo. (OGQ 800), Project Manager of the Windfall Lake gold project, who is a “qualified person” as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).

Quality Control and Reporting Protocols

True widths determinations are estimated at 65-80% of the reported core length intervals for most of the zones. Assays are uncut except where indicated. Intercepts occur within geological confines of major zones but have not been correlated to individual vein domains at this time. Reported intervals include minimum weighted averages of 3.0 g/t Au diluted over core lengths of at least 2.0 metres. All NQ core assays reported were obtained by either 1-kilogram screen fire assay or standard 50-gram fire-assaying-AA finish or gravimetric finish at (i) ALS Laboratories in Val d’Or, Québec, Thunder Bay, Ontario, Sudbury, Ontario or Vancouver, British Colombia, or (ii) Bureau Veritas in Timmins, Ontario. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using an Aqua Regia-ICP-AES method at ALS Laboratories. Drill program design, Quality Assurance/Quality Control (“QA/QC”) 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 included with every 20 samples for QA/QC purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assay.

About the Windfall Lake Gold Deposit

The Windfall Lake gold deposit is located between Val-d’Or and Chibougamau in the Abitibi region of Québec, Canada. The mineral resource defined by Osisko, as disclosed in a press release disseminated by the Corporation on May 14, 2018, comprises 2,382,000 tonnes at 7.85 g/t Au (601,000 ounces) in the indicated mineral resource category and 10,605,000 tonnes at 6.70 g/t Au (2,284,000 ounces) in the inferred mineral resource category (see press release entitled “Osisko Releases Its First Mineral Resource Estimate for Windfall Gold Deposit” dated May 14, 2018, which is available on Osisko’s website at www.osiskomining.com and on SEDAR under Osisko’s issuer profile at www.sedar.com). The Windfall Lake gold deposit is currently one of the highest grade resource-stage gold projects in Canada. Mineralization occurs in four principal zones: Lynx, Zone 27, Caribou, and Underdog. All zones comprise sub-vertical lenses following intrusive porphyry contacts plunging to the northeast. The deposit is well defined from surface to a depth of 900 metres and remains open along strike and at depth. Mineralization has been identified only 30 metres from surface in some areas and as deep as 1,200 metres in others, with significant potential to extend mineralization down-plunge and at depth.

About Osisko Mining Inc.

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% in the high-grade Windfall Lake gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding Urban Barry area and nearby Quevillon area (over 3,300 square kilometres), a 100% interest in the Marban project located in the heart of Québec’s prolific Abitibi gold mining district, and properties in the Larder Lake Mining Division in northeast Ontario, including the Jonpol and Garrcon deposits on the Garrison property, the Buffonta past producing mine and the Gold Pike mine property. The Corporation also holds interests and options in a number of additional properties in northern Québec and Ontario.  Osisko continues to be well financed with approximately $150 million in cash and investments as of March 31, 2018.

Cautionary Note Regarding Forward-Looking Information

This news release contains “forward-looking information” within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. The information in this news release about the Windfall Lake gold deposit being one of the highest grade resource-stage gold projects in Canada; the current 800,000 metre drill program; the significance of the mineral resource estimate published by the Corporation on May 14, 2018 in respect of the Windfall Lake gold deposit; the significance of new results from the ongoing drill program at the Windfall Lake gold project, including in respect of the Lynx deposit; the significance of assay results presented in this press release; the type of drilling included in the drill program (definition, expansion and exploration drilling in and around the main Windfall Lake gold deposit and the adjacent Lynx deposit, and exploration drilling on the greater deposit and Urban-Barry project area); potential mineralization; the potential to extend mineralization up and down-plunge and at depth at the Windfall Lake gold deposit; the ability to realize upon any mineralization in a manner that is economic; the ability to complete any proposed exploration activities and the results of such activities, including the continuity or extension of any mineralization; and any other information herein that is not a historical fact may be “forward-looking information”. Any statement that involves discussions with respect to predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as “expects”, or “does not expect”, “is expected”, “interpreted”, “management’s view”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may” or “could”, “would”, “might” or “will” be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This forward-looking information is based on reasonable assumptions and estimates of management of the Corporation. at the time it was made, involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Osisko to be materially different from any future results, performance or achievements expressed or implied by such forward-looking information. Such factors include, among others, risks relating to the ability of exploration activities (including drill results) to accurately predict mineralization; errors in management’s geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property interests in the Windfall Lake gold project; the ability of the Corporation to obtain required approvals and complete transactions on terms announced; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions. Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information, Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

For further information please contact:

John Burzynski. President and Chief Executive Officer

Telephone: (416) 363-8653