Osisko Development Intersects 2.19 g/t Gold over 78.9 m at Sapuchi and 1.55 g/t Gold over 42.5 m at Golfo De Oro

The Company is also pleased to report, further to its previously-announced non-brokered private placement (the "Non-Brokered Placement") of up to US$110 million of subscription receipts of the Corporation ("Subscription Receipts"), that the Corporation expects to close a first tranche of the Non-Brokered Placement on March 4, 2022 for gross proceeds of approximately US$67.3 million of Subscription Receipts.

The Corporation has also received subscription proceeds or expressions of interest for the remaining Subscription Receipts allotted under the up to US$110 million Non-Brokered Placement, which Osisko Development expects to close, as a second tranche closing, in late March 2022. The Non-Brokered Placement is being completed on a "non-brokered" basis and no commission or finder's fee will be paid by Osisko Development in connection therewith.

San Antonio Drill Results Summary

• A total of 27,900 meters were drilled in 177 holes in 2021. The objective of the drill program was to conduct exploration and resource drilling at a spacing of 25 meters and historic drilling validation for the three main target areas (Figure 1).
• This news releases encompasses all 6,550 meters in 33 holes from the Golfo de Oro Target: GO-DD-21-015 to GO-DD-21-174 inclusive (Figure 2) and the remaining assays from 8,050 meters in 76 holes at Sapuchi: SP-DD-21-060A to SP-DD-21-173 inclusive (Figure 4).
• Assay highlights from Golfo de Oro include 1.55 g/t Au and 2.32 g/t Ag over 42.50 meters in hole GO-DD-21-111 and 2.47 g/t Au and 18.67 g/t Ag over 21.20 meters in hole GO-DD-21-057 including a sample of 18.00 g/t Au and 43.90 g/t Ag over 1.50 meters within the prospective hydrothermal breccia (Figure 2).
• Assay highlights from Sapuchi include 2.19 g/t Au and 4.12 g/t Ag over 78.90 meters in hole SP-DD-21-102 including a high-grade sample of 21.30 g/t Au and 11.75 g/t Ag over 3.20 meters (Figure 4).
• A total of 18 intervals below assayed greater than 1.00 g/t Au over at least 10.0 meters.
• Gold mineralization is hosted within altered hydrothermal breccia and sediments, as stockwork quartz veins and veinlets and adjacent to intrusions and fault structures.
• Detailed drilling results are presented in Table 1, drillhole locations are presented in Table 2, and drillhole cross sections are presented in Figures 3 and 5.
  

Assay Highlights

Sean Roosen, CEO of Osisko Development commented, "The 2021 diamond drill campaign at our San Antonio Project was successful in defining and expanding the known zones as shown by these recent results. The Sapuchi, Golfo de Oro, and California Zones trend for approximately three kilometers and there are at least a dozen other targets at surface that remain unexplored or underexplored along a ten kilometer strike. These results will be incorporated into the mineral resource estimate and used to further determine our next steps for expansion on the project."

The San Antonio Project gold mineralization is characterized by hydrothermal breccia that forms an approximately 3,000 m long east-northeast trending mineralization corridor with the Luz del Cobre copper deposit at the east. The gold mineralization is associated with intense chlorite and carbonate alteration and is intrusion related with host sedimentary rocks. The breccia has been defined to a vertical depth of 500 meters and at an average depth of 250 meters. Drilling has occurred within the three major zones at Sapuchi, Golfo de Oro and California, over a combined strike length of 1 kilometer of the 3 kilometer breccia trend.

True widths are estimated to be 80% to 100% of reported core length intervals. Intervals not recovered by drilling were assigned zero grade. Top cuts have not been applied to high grade assays. Complete assay highlights are presented in Table 1, drill hole locations are listed in Table 2.

Figure 1: San Antonio Mineral Zones overview map is available at:
https://www.globenewswire.com/NewsRoom/AttachmentNg/86320f50-7bff-4628-9090-49ed8916b02b

Figure 2: Golfo de Oro plan map with select drilling highlights is available at:
https://www.globenewswire.com/NewsRoom/AttachmentNg/a86a23db-97d0-4018-a3ec-2f1a53474e49

Figure 3: Golfo de Oro section select drilling highlights is available at:
https://www.globenewswire.com/NewsRoom/AttachmentNg/26ce51cd-0d27-4b29-a62d-98be6dd40518

Figure 4: Sapuchi plan map with select drilling highlights is available at:
https://www.globenewswire.com/NewsRoom/AttachmentNg/ae5e5836-7f08-4701-92d4-26d64a4cfdbe

Figure 5: Sapuchi section select drilling highlights is available at:
https://www.globenewswire.com/NewsRoom/AttachmentNg/43cf7bc3-3230-4e5f-94bc-caa9df40f483

Qualified Persons

Maggie Layman, P.Geo. Vice President Exploration of Osisko Development, and a "qualified person" for purposes of National Instrument 43-101 - Standards of Disclosure for Mineral Projects, has prepared, validated, and approved the scientific and technical content in this news release.

Quality Assurance - Quality Control

Once received from the drill and processed, all drill core samples are sawn in half, labelled and bagged. The remaining drill core is subsequently stored on site at a secured facility at the project site. Numbered security tags are applied to lab shipments for chain of custody requirements. Quality control (QC) samples are inserted at regular intervals in the sample stream, including blanks and reference materials with all sample shipments to monitor laboratory performance.

Drill core samples are submitted to ALS Geochemistry and Bureau Veritas (BV) preparation laboratory in Hermosillo and then sent to their analytical facilities in North Vancouver, British Columbia for analysis. The facilities are accredited to the ISO/IEC 17025 standard for gold assays and all analytical methods include quality control materials at set frequencies with established data acceptance criteria. The entire sample is crushed, and 200 grams is pulverized. Analytical packages for ALS and BV are AA24 and FA450 respectively. Multi Element geochemistry is also analyzed with ME MS61 at ALS and MA 200 at BV.

About Osisko Development Corp.

Osisko Development Corp. is uniquely positioned as a premier gold development company in North America to advance the Cariboo Gold Project and other Canadian and Mexican properties, with the objective of becoming the next mid-tier gold producer. The Cariboo Gold Project, located in central British Columbia, is Osisko Development's flagship asset with measured and indicated resources of 21.44 Mt at 4.6 Au g/t for a total of 3.2 million ounces of gold and inferred resource of 21.69 Mt at 3.9 Au g/t for a total of 2.7 million ounces of gold (see NI 43-101 Technical Report and mineral resource estimate effective October 5, 2020). The considerable exploration potential at depth and along strike distinguishes the Cariboo Gold Project relative to other development assets as does the historically low, all-in discovery costs of US $19 per ounce. The Cariboo Gold Project is advancing through permitting as a 4,750 tonnes per day underground operation with a feasibility study on track for completion in the first half of 2022. Osisko Development's project pipeline is complemented by potential near-term production targeted from the San Antonio gold project, located in Sonora Mexico. Osisko Development began trading on the TSX Venture Exchange under the symbol "ODV" on December 2, 2020 and the Company's 14,789,373 outstanding share purchase warrants were listed on the TSX Venture Exchange under the symbol "ODV.WT" on October 25, 2021.

Forward-looking Statements

Certain statements contained in this press release may be deemed "forward-looking statements" within the meaning of applicable Canadian and U.S. securities laws. These forward-looking statements, by their nature, require Osisko Development to make certain assumptions and necessarily involve known and unknown risks and uncertainties that could cause actual results to differ materially from those expressed or implied in these forward-looking statements. Forward-looking statements are not guarantees of performance. Words such as "may", "will", "would", "could", "expect", "believe", "plan", "anticipate", "intend", "estimate", "continue", or the negative or comparable terminology, as well as terms usually used in the future and the conditional, are intended to identify forward-looking statements. Information contained in forward-looking statements is based upon certain material assumptions that were applied in drawing a conclusion or making a forecast or projection, including management's perceptions of historical trends, current conditions and expected future developments, results of further exploration work to define and expand mineral resources, that exploration work will continue to show significant anomalous results in the oxide, transition and sulphide horizons and indicate continuity near surface and along strike and, open to the west along trend, that the gold mineralization continues to be associated with intense sericite and chlorite alteration and be intrusion related with host sedimentary rocks, that the breccia continues to be defined to a vertical depth of 500 meters and at an average depth of 250 meters, as well as other considerations that are believed to be appropriate in the circumstances. Osisko Development considers its assumptions to be reasonable based on information currently available, but cautions the reader that their assumptions regarding future events, many of which are beyond the control of Osisko Development, may ultimately prove to be incorrect since they are subject to risks and uncertainties that affect Osisko Development and its business. Such risks and uncertainties 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 to complete further exploration activities, including drilling; property and stream interests in the San Antonio gold project; the ability of the Corporation to obtain required approvals; the results of exploration activities; risks relating to exploration, development and mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions and the responses of relevant governments to the COVID-19 outbreak and the effectiveness of such responses.

For additional information with respect to these and other factors and assumptions underlying the forward-looking statements made in this news release concerning Osisko Development, see the Filing Statement available electronically on SEDAR (www.sedar.com) under Osisko Development's issuer profile. The forward-looking statements set forth herein concerning Osisko Development reflect management's expectations as at the date of this news release and are subject to change after such date. Osisko Development disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, other than as required by law.

Neither the 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 news release. No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein.

Table 1: San Antonio Gold Project 2021 Length Weighted Drill Hole Gold and Silver Composites from Golfo de Oro and Sapuchi Zones

Table 2: Drill Hole Locations and Orientations