Mr. Craig MacDougall reports

IAMGOLD REPORTS FIRST MINERAL RESOURCE ESTIMATE FOR THE DIAKHA DEPOSIT, SIRIBAYA PROJECT IN MALIZ

Iamgold Corp. has provided the first mineral resource estimate in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) definition standards incorporated by reference in National Instrument 43-101 for the Diakha deposit located on the Siribaya joint venture project in western Mali, West Africa. With the discovery of the Diakha zone in 2014, Iamgold expanded its exploration drilling program, culminating in the completion of the first mineral resource estimate for the Diakha deposit. The Siribaya exploration project is operated by Iamgold under a 50/50 joint venture with Merrex Gold Inc.

The resource estimate, which includes resources estimated for previously known zones at Zone 1B and Taya Ko (formerly Zone 1A) along the Siribaya trend, as well as the new Diakha deposit, is composed of indicated resources totalling 2.1 million tonnes averaging 1.90 grams of gold per tonne for 129,000 ounces and inferred resources composed of 19.8 million tonnes averaging 1.71 grams of gold per tonne for 1.1 million ounces. A significant portion of the estimate is derived from the newly discovered Diakha deposit, which is open in all directions and has significant potential for expansion.

Craig MacDougall, senior vice-president, exploration, for Iamgold, stated: "The Diakha discovery is the second greenfield discovery made by the Iamgold exploration team in West Africa in the last three years, including the Malikoundi deposit of the Boto gold project located in neighbouring Senegal. Despite reduced budgets resulting from a sustained industrywide downturn, the exploration group has successfully advanced Diakha from discovery to an initial resource estimate in just two years. We believe that there remains significant potential to expand the current resource base, and this will be an objective of future exploration programs. I extend my congratulations to the Diakha discovery team, who have worked very hard to achieve this outstanding result."

The mineral resource for the Diakha deposit incorporates assay results from 216 diamond and reverse circulation drill holes totalling 25,696 metres, and for Zone 1B and Taya Ko zones, and incorporates results from 129 drill holes totalling 3,903 metres. The estimate was prepared using a block model constrained with 3-D wire frames of the principal mineralized domains. Values for gold were interpolated into blocks using inverse distance squared (ID2). A preliminary open-pit optimization algorithm was run on the estimated grade block model to constrain the resource and to support the Canadian Institute of Mining, Metallurgy and Petroleum requirement that mineral resources have reasonable prospects for eventual economic extraction. The resource estimate assumes a long-term gold price of $1,500 (U.S.) per ounce. Only mineralization contained within the preliminary pit shell has been included in the resource estimate.

The mineral resource estimate is summarized in the attached table at cut-off grades ranging from 0.45 to 0.60 gram of gold per tonne. The effective date of this resource estimate is Dec. 31, 2015.

                     SIRIBAYA PROJECT -- MINERAL RESOURCE ESTIMATE                  
                                    (Dec. 31, 2015)
                                                                                
Classification       Zone    Tonnage (000s)   Gold grade (g/t Au)  Contained ounces (Au) (000s)

Indicated         Zone 1B            2,102                  1.90                           129
Total indicated                      2,102                  1.90                           129
                  Zone 1B            4,094                  1.52                           200
Inferred          Taya Ko              882                  1.02                            29
                   Diakha           14,840                  1.81                           863
Total inferred                      19,816                  1.71                         1,092

In support of the mineral resource estimate, preliminary metallurgical testwork was completed by SGS Minerals Services in Lakefield, Ont., on three composite samples prepared from Diakha diamond drill core. The results suggest that the gold mineralization is not refractory and that a gold recovery of approximately 92 per cent can be expected from a conventional leach/carbon-in-pulp circuit.

The Siribaya project consists of 11 contiguous exploration permits, which cover a total area of 876.5 square kilometres, and is located in the Kedougou-Kenieba inlier of the West African Craton region of western Mali along the borders with Senegal and Guinea. The Diakha, Siribaya 1B and Taya Ko deposits are hosted within highly prospective, Birimian-aged metasedimentary, volcanic and intrusive rocks proximal to the Senegal-Mali Shear zone. At Diakha, gold mineralization occurs within an albitized sandstone similar to Iamgold's Boto gold deposit located approximately 10 kilometres to the north along strike. Zone 1B and Taya Ko occur within the north-northeast-trending Siribaya structural trend, which extends over 10 kilometres along strike, and gold mineralization occurs within breccia-hosted stockworks or fault-related silicified zones.

Next steps

The mineralization at Diakha remains open along strike and at depth, where further drilling is warranted. In 2016, the company plans additional drilling to increase its confidence in the current resources and continue to expand the mineralization along strike and at depth.

Qualified persons

The mineral resource estimate, including verification of the data disclosed, has been completed by RPA Inc. and reported in accordance with National Instrument 43-101 requirements and CIM estimation best-practice guidelines. The resource estimate was prepared by RPA principal geologist Luke Evans, PEng, and a supporting NI 43-101 technical report will be posted on SEDAR no later than 45 days after the date of this release. Mr. Evans, who is an independent qualified person under NI 43-101, has reviewed and approved the contents of this release.

Craig MacDougall, PGeo, senior vice-president, exploration, for Iamgold, has also reviewed and approved the contents of this release. Mr. MacDougall is a qualified person as defined by NI 43-101.

We seek Safe Harbor.