Iamgold Reports Additional Positive Results from Its Resource Delineation Drilling Program ON the Gosselin Zone – Côté GOLD Project, Ontario

NEWS RELEASE

TSX: IMG NYSE: IAG

IAMGOLD REPORTS ADDITIONAL POSITIVE RESULTS FROM ITS

RESOURCE DELINEATION DRILLING PROGRAM ON THE

GOSSELIN ZONE – CÔTÉ GOLD PROJECT, ONTARIO

Toronto, Ontario, January 21, 2021 – IAMGOLD Corporation (“IAMGOLD” or the “Company”) is

pleased to announce assay results from its delineation diamond drilling program at the Gosselin Zone

discovery, located approximately 1.5 kilometres northeast of the Côté Gold Project (“Côté”, “Project”). The

Gosselin delineation drilling program is being undertaken as part of the Côté Gold Joint Venture Project, a

70:30 joint venture between IAMGOLD and Sumitomo Metal Mining Co., Ltd. (“SMM”). Côté, located 125

km southwest of Timmins and 175 km north of Sudbury, Ontario, Canada, is currently under construction

with first gold production anticipated in the second half of 2023 (see news release dated July 21, 2020).

Since the fourth quarter of 2019, a total of thirty-three (33) diamond drill holes totaling 13,735 metres were

completed as part of the resource delineation drilling program. The drill holes were variably completed

from collar positions located on either lake ice, or on a floating barge deployed in Three Ducks Lake and

from land based drill pads on the north shore of Three Ducks Lake or on the Young-Shannon peninsula.

IAMGOLD is reporting assay results from twenty-four (24) diamond drill holes totaling 10,049 metres.

Results are pending for the remaining nine (9) drill holes totaling 3,686 metres. These results will be

reported once they are received, validated and compiled.

The assay results reported herein are provided in Table 1, below, and include the following highlights (see

plan map attached to this news release for drill hole locations):

 Drill hole GOS19-30: 264.5 metres grading 0.94 g/t Au

includes: 27.0 metres grading 2.72 g/t Au

includes: 2.6 metres grading 12.87 g/t Au

 Drill hole GOS19-33: 243.6 metres grading 0.99 g/t Au

includes: 142.0 metres grading 1.29 g/t Au

 Drill hole GOS20-38: 202.0 metres grading 1.22 g/t Au

includes: 151.0 metres grading 1.50 g/t Au

 Drill hole GOS20-44: 265.0 metres grading 0.95 g/t Au

includes: 169.0 metre grading 1.26 g/t Au

 Drill hole GOS20-47: 417.3 metres grading 0.95 g/t Au

includes: 197.3 metres grading 1.60 g/t Au

 Drill hole GOS20-48: 164.3 metres grading 1.51 g/t Au

 Drill hole GOS20-49: 353.0 metres grading 1.04 g/t Au

includes: 46.0 metres grading 3.39 g/t Au

 Drill hole GOS20-52: 86.0 metres grading 5.57 g/t Au

includes: 30.35 metres grading 14.70 g/t Au

Craig MacDougall, Executive Vice President, Growth for IAMGOLD, stated: “With the many challenges

faced by the exploration team in 2020, the completion of this diamond drilling campaign was a significant

achievement and has clearly brought into focus and confirmed the im portance of this new discovery. The

program was completed with outstanding safety performance while working cooperatively to coordinate

with the numerous activities of the Côté mine site construction team. We are looking forward with

anticipation to the completion of a maiden resource estimate later this year.”

page 2 of 6

The diamond drilling program was designed to complete in-fill and delineation drilling on the Gosselin and

Young-Shannon zones, at a nominal hole spacing of approximately 75 metres. The program was

successful in confirming the continuity of broad zones of gold mineralization throughout the Gosselin Zone,

at grades similar to the adjacent Côté deposit (see Table 1). As at Côté, mineralization is hosted within

sericite-altered and locally brecciated intrusive lithologies of the Chester Intrusive Complex. Diamond

drilling data collected from this program has provided an increased understanding of the geological,

alteration and structural controls on the Gosselin mineralized system and is being integrated into

exploration models to guide future drilling campaigns. The models suggest upside potential of the

mineralized system in a number of directions, predominately at depth to the northwest, and along str ike to

the east and southwest.

The results of this program together with additional drilling planned in 2021 will be used to support the

completion of a maiden resource estimate later this year.

Next Steps

Assay results will be incorporated into the geologic and structural models for the Gosselin and Young -

Shannon zones to support the planned resource estimate expected later this year. The 2021 exploration

program will include the completion of approximately 14,500 metres of diamond drilling to continue to

delineate and expand the mineralized zone.

Elsewhere on the property, additional exploration drilling will begin to evaluate other identified targets

along the developing mineralized trend of the Côté deposit and the Gosselin zone.

Figure 1 – Gosselin Zone Drill Hole surface plan and highlighted 2019-2020 assay

page 3 of 6

Hole No. AZ DIP EOH From To Core

Interval (1) Au (2)

Easting Northing Elevation (°) (°) (m) (m) (m) (m) (g/t)  

GOS19-30 430976 5268042 389 182 -59 534.00 212.00 534.00 322.00 0.81

Including (3) 260.50 525.00 264.50 0.94

Including (3) 357.00 358.00 1.00 12.40

Including (3) 469.00 496.00 27.00 2.72

Including (3) 470.14 472.74 2.60 12.87

Including (3) 513.33 514.00 0.67 17.40

GOS19-31 430938 5267866 382 332 -65 411.00 236.00 408.28 172.28 0.56

Including (3) 311.00 408.28 97.28 0.71

GOS19-32 430859 5267893 386 190 -60 474.00 6.00 16.00 10.00 0.68

158.92 425.85 266.93 0.45

GOS19-33 430960 5267540 383 333 -60 476.00 45.00 476.00 431.00 0.71

Including (3) 164.41 408.00 243.59 0.99

Including (3) 242.00 384.00 142.00 1.29

GOS20-34 430778 5267425 392 330 -60 426.00 298.00 426.00 128.00 0.60

Including (3) 379.05 426.00 46.95 0.74

GOS20-35 430845 5267360 390 328 -58 426.00 114.62 164.00 49.38 0.90

Including (3) 124.25 125.05 0.80 14.80

263.00 426.00 163.00 0.65

Including (3) 317.05 393.00 75.95 0.89

GOS20-36 430872 5267441 383 330 -60 450.00 169.00 184.00 15.00 0.61

266.00 319.00 53.00 0.53

327.70 360.40 32.70 0.74

368.00 450.00 82.00 0.57

GOS20-37 430877 5267549 382 325 -60 510.00 212.00 315.23 103.23 0.80

Including (3) 248.00 249.00 1.00 11.70

Including (3) 289.78 290.31 0.53 28.30

321.00 451.00 130.00 0.65

GOS20-38 431117 5267597 381 330 -60 426.00 145.00 186.00 41.00 0.72

Including (3) 145.00 146.00 1.00 11.90

224.00 426.00 202.00 1.22

275.00 426.00 151.00 1.50

GOS20-39 430918 5267645 381 331 -60 244.00 50.97 68.14 17.17 0.67

GOS20-40 431115 5267712 381 330 -60 432.00 42.00 53.00 11.00 0.76

257.00 432.00 175.00 0.99

Including (3) 392.00 393.00 1.00 10.50

GOS20-41 430851 5267705 381 330 -60 426.00 54.48 130.00 75.52 0.37

135.00 249.00 114.00 0.80

Including (3) 176.00 178.97 2.97 6.09

257.00 290.00 33.00 1.01

Table 1 Gosselin Project Drilling Results - 2019-2020 Drilling program

UTM NAD83 Zone17

page 4 of 6

Notes:

1. Insufficient drilling has been completed to accurately determine the Gosselin Zone orientation. Actual core widths are

estimated at approximately 60 to 95% of the core interval.

2. Drill hole intercepts are calculated with a lower cut of 0.30 g/t Au.

3. Assays are reported uncut but high grade sub-intervals are highlighted.

4. GOS20-52 Core Interval 78.65 to 109.00 m has actual core widths estimated to be 26.6% of the core interval.

* BTW drill core. Core diameter is 42.0 mm

GOS20-42 430985 5267677 381 336 -60 423.00 203.00 338.00 135.00 0.70

365.00 391.00 26.00 0.38

GOS20-43 430998 5267506 381 330 -60 432.00 212.00 430.00 218.00 0.92

GOS20-44 431072 5267543 381 327 -60 438.00 169.00 434.00 265.00 0.95

Including (3) 265.00 434.00 169.00 1.26

Including (3) 398.50 399.00 0.50 18.80

GOS20-45 431247 5267757 381 330 -60 76.00

GOS20-46* 431148 5267656 381 330 -60 432.00 163.00 188.00 25.00 1.33

Including (3) 169.00 170.00 1.00 24.20

318.00 432.00 114.00 0.61

GOS20-47* 431273 5267656 380 340 -60 438.30 21.00 438.30 417.30 0.95

Including (3) 241.00 438.30 197.30 1.60

Including (3) 301.70 303.00 1.30 41.30

GOS20-48* 431200 5267631 380 328 -66 421.31 257.00 421.31 164.31 1.51

Including (3) 380.00 381.00 1.00 14.40

GOS20-49* 431252 5267761 381 336 -61 430.47 65.00 418.00 353.00 1.04

Including (3) 124.00 170.00 46.00 3.39

Including (3) 132.00 133.00 1.00 10.40

Including (3) 140.00 141.05 1.05 13.40

Including (3) 147.00 148.00 1.00 18.30

Including (3) 232.63 233.53 0.90 12.50

GOS20-50* 431229 5267823 380 329 -60 437.28 27.00 67.81 40.81 0.42

345.00 437.28 92.28 0.64

Including (3) 432.00 433.00 1.00 17.00

GOS20-51* 430731 5267552 388 308 -68 425.68 239.00 284.70 45.70 0.79

Including (3) 255.00 256.00 1.00 11.40

319.36 418.00 98.64 0.76

GOS20-52* (4) 431156 5267837 381 328 -61 424.66 42.00 128.00 86.00 5.57

Including (3) 78.65 109.00 30.35 14.70

Including (3) 83.47 84.85 1.38 27.00

Including (3) 90.00 90.95 0.95 87.80

Including (3) 93.18 94.65 1.47 32.18

Including (3) 102.66 105.00 2.34 76.42

324.00 392.00 68.00 0.66

GOS20-53* 431076 5267837 381 330 -60 435.00 317.00 435.00 118.00 1.11

361.00 362.00 1.00 12.50

425.00 426.00 1.00 24.10

10048.70

Abandoned; re-collared GOS20-49

page 5 of 6

Technical Information and Quality Control Notes

The drilling results contained in this news release have been prepared in accordance with National

Instrument 43-101 Standards of Disclosure for Mineral Projects.

The Qualified Person (“QP”) responsible for the supervision of the preparation, verification and review of

the technical information in this release is Al Smith, P. Geo, District Manager – Exploration for IAMGOLD

in the Ontario Côte District. He is considered a QP for the purposes of National Instrument

43-101 with respect to the technical information being reported on.

The QP responsible for the planning, supervision and execution of the diamond drilling program is Brad

McKinley, P. Geo, Senior Geologist for IAMGOLD in the Ontario Côte District. The technical information

has been included herein with the consent and prior review of the above noted QPs.

The information in this news release was reviewed and approved by Craig MacDougall, P.Geo., Executive

Vice President, Growth for IAMGOLD. Mr. MacDougall is a QP as defined by National Instrument 43-101.

The sampling of, and assay data from, the drill core is monitored through the implementation of a quality

assurance - quality control (QA-QC) program designed to follow industry best practice. Drill core (NQ size)

samples are selected by the IAMGOLD geologists and sawn in half with a diamond saw at the project site.

Half of the core is retained at the site for reference purposes. Sample intervals may vary from half a metre

to one and a half metres in length depending on the geological observations. Samples were stored in

sealed plastic bags and packed into fiber backs onto a pallet where they were shrink wrapped for

transport. A formal chain-of-custody procedure was adopted for security of samples until their delivery at

the laboratory.

Activation Laboratories Limited (ACTLABS - located in Timmins, Ontario) was utilized for assay analyses,

performing crushing, pulverizing, and fire assay in Timmins Ontario. Activation Laboratories complete d the

following laboratory procedure: Samples are coarse crushed to 90% passing 2.0 mm screen (10 mesh

screen), riffle split (250 gram) and (mild steel) to 95% passing 105µm. Cleaner sand is included. Samples

were analyzed using a standard 30 gram fire assay (30 g aliquot) with an Atomic Absorption (AA) finish.

For samples that returned assay values over 3.0 grams per tonne (g/t), another cut is taken from the

original pulp and fire assayed with a gravimetric finish. For samples showing visible gold (VG) or samples

which have returned values greater than 5.0 g/t, these were re-analyzed by pulp metallic analysis.

IAMGOLD inserts blanks and certified reference standards in the sample sequence for quality control.

In accordance with recommendations from our on-going QA-QC program, additional check analyses are

underway at ACTLABS

CAUTIONARY STATEMENT ON FORWARD-LOOKING INFORMATION

This news release contains forward-looking statements. All statements, other than of historical fact, that address activities,

events or developments that the Company believes, expects or anticipates will or may occur in the future are forward-looking

statements. Forward-looking statements are generally identifiable by, but not limited to, the use of the words “may”, “will”,

“should”, “continue”, “expect”, “budget”, “forecast”, “anticipate”, “estimate”, “believe”, “prospective”, “significant”, “potential”,

“significant potential”, “substantial”, “transformative”, “intend”, “plan” or “project” or the negative of these words or other

variations on these words or comparable terminology. Forward-looking statements are subject to a number of risks and

uncertainties, many of which are beyond the Company’s ability to control or predict, that may cause the actual results of the

Company to differ materially from those discussed in the forward-looking statements. Factors that could cause actual results

or events to differ materially from current expectations include, among other things, without limitation, failure to meet

expected, estimated or planned gold production, unexpected increases in all-in sustaining costs or other costs, unexpected

increases in capital expenditures and exploration expenditures, variation in the mineral content within the material identified

as Mineral Resources and Mineral Reserves from that predicted, changes in development or mining plans due to changes in

logistical, technical or other factors, the possibility that future exploration results will not be consistent with the Company's

expectations, changes in world gold markets and other risks disclosed in IAMGOLD’s most recent Form 40-F/Annual

Information Form on file with the United States Securities and Exchange Commission and Canadian securities regulatory

authorities. Any forward-looking statement speaks only as of the date on which it is made and, except as may be required by

applicable securities laws, the Company disclaims any intent or obligation to update any forward-looking statement. The

Company disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new

information, future events or otherwise except as required by applicable law.

page 6 of 6

About IAMGOLD

IAMGOLD is a mid-tier mining company with three gold mines on three continents, including the Essakane

mine in Burkina Faso, the Rosebel mine in Suriname, and the Westwood mine in Canada. A solid base of

strategic assets is complemented by the Côté Gold construction project in Canada, the Boto Gold

development project in Senegal, as well as greenfield and brownfield exploration projects in various

countries located in West Africa and the Americas. IAMGOLD aims to become a million-ounce gold producer

as it executes on its growth strategy, including bringing Côté Gold, its fourth mine, online.

IAMGOLD is committed to maintaining its culture of accountable mining through high standards of ESG

practices and employs approximately 5,000 people. IAMGOLD’s commitment is to Zero Harm, in every

aspect of its business. IAMGOLD is one of the companies on the JSI index.

IAMGOLD is listed on the Toronto Stock Exchange (trading symbol “IMG”) and the New York Stock

Exchange (trading symbol “IAG”).

For further information please contact:

Indi Gopinathan, VP, Investor Relations & Corporate Communications, IAMGOLD Corporation

Tel: (416) 360-4743 Mobile: (416) 388-6883

Philip Rabenok, Senior Analyst, Investor Relations, IAMGOLD Corporation

Tel: (416) 933-5783 Mobile: (647) 967-9942

Toll-free: 1-888-464-9999 [email protected]

Please note:

This entire news release may be accessed via fax, e-mail, IAMGOLD's website at www.iamgold.com and through Newsfile’s website

at www.newsfilecorp.com. All material information on IAMGOLD can be found at www.sedar.com or at www.sec.gov.

Si vous désirez obtenir la version française de ce communiqué, veuillez consulter le www.iamgold.com/French/Home/default.aspx.