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OSISKO DEVELOPMENT REPORTS 2022 DRILL RESULTS AT TRIXIE, INCLUDING: 53.27 g/t Au and 90.24 g/t Ag over 2.44 m and 36.81 g/t Au and 30.89 g/t Ag over 3.35 m

Drill Results

NYSE: ODV TSXV: ODV NEWS RELEASE

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OSISKO DEVELOPMENT REPORTS 2022 DRILL RESULTS AT TRIXIE, INCLUDING:

53.27 g/t Au and 90.24 g/t Ag over 2.44 m and 36.81 g/t Au and 30.89 g/t Ag over 3.35 m

Montreal, Québec, May 4, 2023 – Osisko Development Corp. (NYSE: ODV, TSXV: ODV) ("Osisko

Development" or the "Company") is pleased to announce underground diamond drilling ("DD") results as

part of its ongoing exploration program at its 100%-owned Trixie test mine ("Trixie"), within the Company's

wider Tintic Project ( "Tintic" or the " Tintic Project"), located in the historic East Tintic Mining District in

central Utah, U.S.A.

Chris Lodder, President of Osisko Development, commented, "These drill results from the 2022

underground diamond drilling campaign continue to showcase the continuity of the high -grade

mineralization within the T2 structure and wider zones of mineralization within the T4 stockwork zone. Our

current underground dri ll program is building upon these results and this work is expected to support a

future update to the existing Trixie mineral resource estimate."

DRILL ASSAY HIGHLIGHTS

This news release includes assays from 8 DD holes (refer to Table 1). Select assay highlights include:

• 128.50 grams per tonne ("g/t") gold ("Au") and 220.00 g/t silver ("Ag") over 0.52 meters ("m") in

hole TUG-625-034 (3.75 troy ounces per short ton ("oz/t") Au and 6.42 oz/t Ag over 1.70 feet ("ft.")

• 17.63 g/t Au and 175.81 g/t Ag over 3.96 m in hole TUG -625-034 (0.51 oz/t Au and 5.1 3 oz/t Ag

over 13.00 ft.)

• 7.51 g/t Au and 50.19 g/t Ag over 5.79 m in hole TUG-625-034 (0.22 oz/t Au and 1.46 oz/t Ag over

19.00 ft.)

• 36.81 g/t Au and 30.89 g/t Ag over 3.35 m in hole TUG -625-036 (1.07 oz/t Au and 0.90 oz/t Ag

over 11.00 ft.) including

o 134.50 g/t Au and 65.00 g/t Ag over 0.61 m (3.92 oz/t Au and 1.90 oz/t Ag over 2.00 ft.)

• 20.88 g/t Au and 45.08 g/t Ag over 5.6 4 m in hole TUG -625-037 (0.61 oz/t Au and 1.31 oz/t Ag

over 18.50 ft.) including

o 154.00 g/t Au and 397.00 g/t Ag over 0.46 m (4.49 oz/t Au and 11.58 oz/t Ag over 1.50 ft.)

• 53.27 g/t Au and 90.24 g/t Ag over 2.4 4 m in hole TUG -625-037 (1.55 oz/t Au and 2.63 oz/t Ag

over 8.00 ft.) including

o 105.50 g/t Au and 177.00 g/t Ag over 0.91 m (3.08 oz/t Au and 5.16 oz/t Ag over 3.00 ft.)

• 84.40 g/t Au and 301.00 g/t Ag over 0.73 m in hole TUG-625-085 (2.46 oz/t Au and 8.7 8 oz/t Ag

over 2.40 ft.)

• 15.61 g/t Au and 163.56 g/t Ag over 2.4 4 m in hole TUG-625-085 (0.46 oz/t Au and 4.77 oz/t Ag

over 8.00 ft.)

• 10.78 g/t Au and 38.15 g/t Ag over 3.96 m in hole TUG-625-094 (0.31 oz/t Au and 1.11 oz/t Ag

over 13.0 ft.)

• 57.50 g/t Au and 246.00 g/t Ag over 0.76 m in hole TUG -625-094 (1.68 oz/t Au and 7.18 oz/t Ag

over 2.50 ft.)

• 78.80 g/t Au and 106.00 g/t Ag over 0.64 m in hole TUG -625-100 (2.30 oz/t Au and 3.09 oz/t Ag

over 2.10 ft.)

• 42.10 g/t Au and 69.90 g/t Ag over 1.37 m in hole TUG -625-100 (1.23 oz/t Au and 2.0 4 oz/t Ag

over 4.50 ft.)

• 16.86 g/t Au and 60.26 g/t Ag over 4.54 m in hole TUG -625-100 (0.49 oz/t Au and 1.7 6 oz/t Ag

over 14.90 ft.)

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• 30.80 g/t Au and 114.00 g/t Ag over 2.26 m in hole TUG-625-100 (0.90 oz/t Au and 3.33 oz/t Ag

over 7.40 ft.)

DRILL SUMMARY

• The high-grade intercepts disclosed in this news release are located within the T2 structure and T4

stockwork in the central and southern areas of the current Trixie Mineral Resource Estimate ("Trixie

MRE") (see Figure 2). These drilling results will provide valuable infill data in order to improve our

understanding and the confidence level of the mineralized zones defined in the Trixie MRE.

• The T2 structure continues to intersect high-grade mineralization including 53.27 g/t Au and 90.24

g/t Ag over 2.44 m in hole TUG-625-037 and 30.80 g/t Au and 114.00 g/t Ag over 2.26 m in hole

TUG-625-100 (see Figure 3).

• The T4 stockwork zone returned several anomalous intervals, displaying both high-grade structures

analogous to the T2 structure and wider mineralized zones as seen in hole TUG -625-037 that

intersected 20.88 g/t Au and 45.08 g/t Ag over 5.64 m and 42.00 g/t Au and 60.40 g/t Ag over 0.76

m (including 154.00 g/t Au and 397.00 g/t Ag over 0.46 m).

EXPLORATION NEXT STEPS

• The Company currently has two underground diamond drill rigs in operation at Trixie conducting

exploration activities.

• Follow up exploration targets include drill testing of the contact beneath the Ophir Shale cap rock,

where mineralization appears to be concentrated, as well as testing the 75-85 structure at depth.

• In 2022, the Company completed 28 surface reverse circulation ( "RC") drill holes near Trixie

totalling approximately 8,753 m (28,718 ft.) and 66 underground DD holes in the 625 level at Trixie

totalling approximately 2,985 m (9,796 ft.). To date, assays have been received for 8 RC drill holes

and 64 DD holes.

About Trixie

The Trixie test mine is one of several gold and base metal targets within the larger Tintic Project consisting

of >17,000 acres of patented mining claims and mineral leases within the historic East Tintic Mining District

of Central Utah, U.S.A. The T2 and T4 structures at Trixie show multi -ounce gold grades associated with

high sulphidation epithermal mineralization, structurally controlled and hosted within quartzites. The T2

structure mineralization consists of native Au, and rare Au-Ag – rich telluride minerals with quartz. The T4

is a mineralized stockwork zone is located in the hanging wall of the T2 and is comprised of Au -Ag rich

mineralization in host rock quartzite with quartz-barite-sulphosalt stockwork veining. Mineralization reports

consistent multi-ounce gold grades along the entire strike length.

Information relating to the Tintic Project and the Trixie MRE is supported by the technical report titled " NI

43-101 Technical Report, Initial Mineral Resource Estimate for the Trixie Deposit, Tinti c Project, Utah,

United States of America", dated January 27, 2023 (with an effective date of January 10, 2023) prepared

for the Company by independent representatives of Micon International Limited (the "Tintic Technical

Report"). Reference should be made to the full text of the Tintic Technical Report, which was prepared in

accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects ("NI 43-101")

and is available electronically on SEDAR ( www.sedar.com) and on EDGAR (www.sec.gov) under Osisko

Development's issuer profile and on the Company's website at www.osiskodev.com.

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Figure 1: Trixie Project Area

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Figure 2: Drill Plan Map

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Figure 3: Cross Section of Underground Drilling at 625 L at Trixie

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Table 1: Drilling Length Weighted Assay Composites at Trixie

METRIC IMPERIAL

Hole ID Depth

from (m)

Depth to

(m)

Length

(m) Au (g/t) Ag (g/t) Depth

from (ft.)

Depth to

(ft.)

Length

(ft.) Au (oz/t) Ag (oz/t) Comments

TUG-625-034 2.23 2.74 0.52 128.50 220.00 7.30 9.00 1.70 3.75 6.42 T4

TUG-625-034 16.61 20.57 3.96 17.63 175.81 54.50 67.50 13.00 0.51 5.13 T4

TUG-625-034 25.76 31.55 5.79 7.51 50.19 84.50 103.50 19.00 0.22 1.46 T4

TUG-625-034 Including 26.37 28.04 1.68 9.99 17.25 86.50 92.00 5.50 0.29 0.50 T4

TUG-625-034 and 30.48 31.55 1.07 22.90 234.00 100.00 103.50 3.50 0.67 6.83 T4

TUG-625-034 33.83 34.44 0.61 7.59 99.00 111.00 113.00 2.00 0.22 2.89 T4

TUG-625-036 0.91 4.27 3.35 36.81 30.89 3.00 14.00 11.00 1.07 0.90 T4

TUG-625-036 Including 0.91 1.83 0.91 32.10 38.30 3.00 6.00 3.00 0.94 1.12 T4

TUG-625-036 and 1.83 2.44 0.61 134.50 65.00 6.00 8.00 2.00 3.92 1.90 T4

TUG-625-037 1.37 7.01 5.64 20.88 45.08 4.50 23.00 18.50 0.61 1.31 T4

TUG-625-037 Including 2.13 2.65 0.52 10.70 23.00 7.00 8.70 1.70 0.31 0.67 T4

TUG-625-037 and 5.18 5.94 0.76 42.00 60.40 17.00 19.50 2.50 1.23 1.76 T4

TUG-625-037 and 6.55 7.01 0.46 154.00 397.00 21.50 23.00 1.50 4.49 11.58 T4

TUG-625-037 9.60 12.04 2.44 53.27 90.24 31.50 39.50 8.00 1.55 2.63 T2

TUG-625-037 Including 10.52 11.43 0.91 105.50 177.00 34.50 37.50 3.00 3.08 5.16 T2

TUG-625-037 and 11.43 12.04 0.61 44.60 75.30 37.50 39.50 2.00 1.30 2.20 T2

TUG-625-037 18.99 19.51 0.52 4.67 10.90 62.30 64.00 1.70 0.14 0.32 T2 FW

TUG-625-071 35.87 37.34 1.46 2.26 7.27 117.70 122.50 4.80 0.07 0.21 T4

TUG-625-082 2.74 4.11 1.37 14.27 66.52 9.00 13.50 4.50 0.42 1.94 T4

TUG-625-082 Including 3.66 4.11 0.46 37.10 81.30 12.00 13.50 1.50 1.08 2.37 T4

TUG-625-082 6.71 7.16 0.46 9.07 72.60 22.00 23.50 1.50 0.26 2.12 T4

TUG-625-082 10.97 11.43 0.46 16.45 18.45 36.00 37.50 1.50 0.48 0.54 T4

TUG-625-085 2.16 2.90 0.73 84.40 301.00 7.10 9.50 2.40 2.46 8.78 T4

TUG-625-085 23.47 25.91 2.44 15.61 163.56 77.00 85.00 8.00 0.46 4.77 T4

TUG-625-085 24.38 25.15 0.76 32.20 283.00 80.00 82.50 2.50 0.94 8.25 T4

TUG-625-085 28.04 29.11 1.07 3.46 48.80 92.00 95.50 3.50 0.10 1.42 T4

TUG-625-094 1.52 2.83 1.31 26.70 104.00 5.00 9.30 4.30 0.78 3.03 T4

TUG-625-094 17.37 21.34 3.96 10.78 38.15 57.00 70.00 13.00 0.31 1.11 T2

TUG-625-094 Including 19.20 19.96 0.76 25.70 64.20 63.00 65.50 2.50 0.75 1.87 T2

TUG-625-094 30.78 31.55 0.76 57.50 246.00 101.00 103.50 2.50 1.68 7.18 T2 Footwall

TUG-625-100 2.13 5.82 3.69 20.47 7.00 19.10 12.10 0.60 0.00 T4

TUG-625-100 Including 3.66 4.11 0.46 34.00 94.70 12.00 13.50 1.50 0.99 2.76 T4

TUG-625-100 and 5.18 5.82 0.64 78.80 106.00 17.00 19.10 2.10 2.30 3.09 T4

TUG-625-100 11.13 12.50 1.37 42.10 69.90 36.50 41.00 4.50 1.23 2.04 T4

TUG-625-100 16.92 21.46 4.54 16.86 60.26 55.50 70.40 14.90 0.49 1.76 T2

TUG-625-100 19.20 21.46 2.26 30.80 114.00 63.00 70.40 7.40 0.90 3.33 T2

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Qualified Persons

The scientific and technical information contained in this news release has been reviewed and approved

by Maggie Layman, P.Geo., Vice President, Exploration of Osisko Development, and a "qualified person"

within the meaning of NI 43-101.

Quality Assurance (QA) – Quality Control (QC)

True width determination is estimated to be approximately 0.3 m to 2.4 m (1 to 8 ft.) wide for the T2 structure

and approximately 3 m to 25 m (10 to 80 ft.) for the T4 mineralized stockwork zone located in the hanging

wall of the T2 structure. All drill core and exploration samples are dispatched to ALS Laboratory for offsite

sample preparation and analysis. Samples are assigned a unique sample ID. All geological and sampling

information is entered into Datamine Fusion database. Core is sawn in half and half are sampled. Certified

standards and blanks inserted into all sample dispatches. Samples are collected by Old Dominion

Transportation and dispatched to ALS Laboratory in Reno, NV. Sample submission forms accompany the

samples, and digital copies emailed to ALS.

All sample preparation is completed by ALS, including crushing and pulverizing (Prep31) of samples.

Analytical assays include gold and silver by fire assay of 50 g sample with AAS finish (Au-AA26), over limits

by gravimetric analysis (Au -Grav22). Multi element analysis is by four acid digest (ME -MS61). The pulps

are returned to Osisko Development and coarse rejects are disposed after 90 days. Assays are reported

to Osisko Development, and then loaded into Datamine Fusion, QA/QC samples are checked, and assays

merged with sample information for future reporting.

About Osisko Development Corp.

Osisko Development Corp. is a premier North American gold development company focused on high-quality

past-producing properties located in mining friendly jurisdictions with district scale potential. The Company's

objective is to become an intermediate gold producer by advancing its 100%-owned Cariboo Gold Project,

located in central BC, Canada, the Tintic Project in the historic East Tintic mining district in Utah, U.S.A.,

and the San Antonio Gold Project in Sonora, Mexico. In addition to considerable brownfield exploration

potential of these properties, that benefit from significant historical mining data, existing infrastructure and

access to skilled labour, the Company's project pipeline is complemented by other prospective exploration

properties. The Company 's strategy is to develop attractive, long -life, socially and environmen tally

sustainable mining assets, while minimizing exposure to development risk and growing mineral resources.

For further information, please contact Osisko Development Corp.:

Sean Roosen Philip Rabenok

Chairman and CEO Director, Investor Relations

Email: [email protected] Email: [email protected]

Tel: +1 (514) 940-0685 Tel: +1 (437) 423-3644

CAUTIONARY STATEMENTS

Cautionary Statement Regarding Test Mining Without Feasibility Study

The Company cautions that the decision to commence small-scale underground mining activities and batch vat leaching at the Trixie

test mine has been made without the benefit of a feasibility study, or reported mineral resources or mineral reserves, demons trating

economic and technical viability, and, as a result there may be increase d uncertainty of achieving any particular level of recovery of

material or the cost of such recovery. The Company cautions that historically, such projects have a much higher risk of economic and

technical failure. Small scale test-mining at Trixie was suspended in December 2022, if and when test mining re-commences there is

no guarantee that production will continue as anticipated or at all or that anticipated production costs will be achieved. Th e failure to

continue production may have a material adverse impact on the Company's ability to generate revenue and cash flow to fund

operations. Failure to achieve the anticipated production costs may have a material adverse impact on the Company's cash flow and

potential profitability. In continuing current oper ations at Trixie after closing, the Company will not be basing its decision to continue

such operations on a feasibility study, or reported mineral resources or mineral reserves demonstrating economic and technica l

viability. The Company cautions that mining at Trixie could be suspended at any time.

Cautionary Statement to U.S. Investors

The Company is subject to the reporting requirements of the applicable Canadian securities laws, and as a result reports info rmation

regarding mineral properties, mineralization and estimates of mineral reserves and mineral resources, including the information in the

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Technical Reports, the Financial Statements, MD&A and this news release, in accordance with Canadian reporting requirements,

which are governed by NI 43-101. As such, such information concerning mineral properties, mineralization and estimates of mineral

reserves and mineral resources, including the information in the Technical Report s, the Financial Statements, MD&A and this news

release, is not comparable to similar information made public by U.S. companies subject to the reporting and disclosure requirements

of the U.S. Securities and Exchange Commission ("SEC").

CAUTION REGARDING FORWARD LOOKING STATEMENTS

Certain statements contained in this news release may be deemed "forward -looking statements" within the meaning of the United

States Private Securities Litigation Reform Act of 1995 and "forward-looking information" within the meaning of applicable Canadian

securities legislation. 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 t hose

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; the utility and significance of historic data, including the significance of the district h osting past

producing mines; future mining activities; the unique mineralization at Trixie; the potential of high grade gold mineralization on Trixie;

the results (if any) of further exploration work to define and expand mineral resources; the ability of exploration work (including drilling)

to accurately predict mineralization; the ability to generate additional drill targets; the ability of management to understand the geology

and potential of Trixie; the ability of the Company to expand mineral resources beyond current mineral resource estimates at Trixie;

the timing and ability of the Company to complete upgrades to the Trixie MRE (or any subsequent MRE) (if at all); the timing and

resumption of test mining activities at Trixie; the information and the sco pe of the contemplated Trixie MRE (and any subsequent

MRE); the impact of the Trixie MRE; the ability of the Company to complete its exploration objectives in 2023 in the timing

contemplated (if at all); the ongoing advancement of the Trixie decline; the deposit remaining open for expansion at depth and down

plunge; the ability to realize upon any mineralization in a manner that is economic; as well as other considerations that are believed

to be appropriate in the circumstances, and any other information h erein that is not a historical fact may be "forward looking

information". Material assumptions also include, management's perceptions of historical trends, the ability of exploration (i ncluding

drilling) to accurately predict mineralization, budget constra ints and access to capital on terms acceptable to the Company, current

conditions and expected future developments, results of further exploration work to define or expand any mineral resources, 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 Deve lopment, 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 rela ting to

capital market conditions and the Company 's ability to access capital on terms acceptable to the Company for the contemplated

exploration and development at Tintic; the ability to continue current operations and exploration; regulatory framework and presence

of laws and regulations that may impose restrictions on mining; the ability of exploration activities (including drill results) to accurately

predict mineralization; errors in management's geological modelling; the ability to expand operations or complete further exploration

activities, including drilling; property and stream interests in the Tintic Project; the ability of the Company to obtain required approvals

and permits; the results of exploration activities; risks relating to exploration, development and mining activities; the global economic

climate; metal and commodity prices; fluctuations in the currency markets; dilution; environmental risks; and community , non-

governmental and governmental actions and the impact of stakeholder actions. Readers are urged to consult the disclosure provided

under the heading "Risk Factors" in the Company's annual information form for the year ended December 31, 202 2, as well as the

Financial Statements and MD&A for the year ended December 31, 2022, which have been filed on SEDAR (www.sedar.com) under

Osisko Development's issuer profile and on the SEC's EDGAR website (www.sec.gov), for further information regarding the risks

and other factors applicable to the exploration results. Although the Company's believes the expectations conveyed by the for ward-

looking statements are reasonable based on information available as of the date hereof, no assurances can be given as to future

results, levels of activity and achievements. The Company disclaims any obligation to update any forward -looking statements,

whether as a result of new information, future events or results or otherwise, except as required by law. Forward-looking statements

are not guarantees of performance and there can be no assurance that these forward-looking statements will prove to be accurate,

as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not

place undue reliance on forward-looking statements.

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.