All monetary amounts are expressed in U.S. dollars, unless otherwise indicated.

Toronto, Ontario--(Newsfile Corp. - February 2, 2023) - IAMGOLD Corporation (TSX: IMG) (NYSE: IAG) ("IAMGOLD" or the "Company") is pleased to announce additional assay results from its ongoing diamond drilling program at the Gosselin zone discovery, located immediately adjacent to the Côté Gold deposit in Ontario, Canada. The Gosselin delineation drilling program is being undertaken as part of the Côté Gold joint venture between IAMGOLD, as the operator, and Sumitomo Metal Mining Co., Ltd. ("SMM"). Côté Gold is currently under construction and is expected to commence production in early 2024 (refer to Company news releases dated November 8, 2022).

Highlights include:

342.2 meters ("m") at 1.99 grams per tonne gold ("g/t Au") in drill hole GOS22-105 from 206.9 m including
101.8 m at 3.05 g/t Au from 311.0 m;
89.0 m at 2.48 g/t Au from 459.0 m
313.0 m at 1.29 g/t Au in drill hole GOS22-126 from 511.0 m including
75.0 m at 3.68 g/t Au from 523.0 m
181.0 m at 1.50 g/t Au in drill hole GOS22-129 from 512.0 m including
91.3 m at 2.55 g/t Au from 582.0 m
388.5 m at 0.66 g/t Au in drill hole GOS22-118 from 39.0 m including
156.5 m at 1.03 g/t Au from 271.0 m
262.0 m at 0.77 g/t Au in drill hole GOS22-122 from 141.0 m

220.5 m at 0.74 g/t Au in drill hole GOS22-116 from 193.5 m including
69.5 m at 1.76 g/t Au from 344.5 m
Craig MacDougall, Executive Vice President, Growth for IAMGOLD, stated: "We are very pleased to see that the results from the 2022 drilling program support the anticipated expansion potential at Gosselin, specifically south of and below the interpreted resource boundaries of the deposit model. Future drilling programs at Gosselin will continue to target the extensions of the deposit towards the goal of defining further potential resource expansion and resource classification upgrades. The 2022 drilling campaign required considerable coordination between the exploration and construction teams during a period of extensive construction activities related to the development of the Côté Gold project. I want to congratulate our exploration team, service contractors, local community employees and partners who together continue to drive the success of our exploration efforts."

IAMGOLD is reporting assay results from an additional twenty-seven (27) diamond drill holes totaling 14,660 metres completed between January 21 and November 13, 2022. The assay results reported are provided in Table 1 below (refer to plan map for drill hole locations outlined in Figure 1).

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