Iamgold Reports Further High Grade Drill Intersections at Its Diakha Deposit, Siribaya Project IN Mali

NEWS RELEASE

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TSX: IMG NYSE: IAG

IAMGOLD REPORTS FURTHER HIGH GRADE DRILL INTERSECTIONS AT ITS

DIAKHA DEPOSIT, SIRIBAYA PROJECT IN MALI

TORONTO, October 18, 2018 – IAMGOLD Corporation (“IAMGOLD” or the “Company”) today provided

results from its 2018 drilling program at the Diakha deposit on its wholly owned Siribaya Project in Western

Mali. In 2018, the Company completed a combined diamond and Reverse Circulation (“RC”) drilling

program designed to infill and increase confidence in the current resource as well as target expansions of

the Diakha deposit to support an updated resource estimate. Assay results are reported herein for 100

drill holes totaling 14,634 metres.

Assay intersections relating to this release are provided in Tables 1 and 2, and include the following

highlights: (a drill hole plan map is attached to this news release.)

Infill Drill Holes:

 SRD18-241: 8.0 metres grading 8.31 g/t Au

o Includes 5.0 metres grading 11.93 g/t Au

and 6.0 metres grading 10.15 g/t Au

o Includes 3.0 metres grading 19.80 g/t Au

 SRD18-249: 13.0 metres grading 6.05 g/t Au

o Includes 5.0 metres grading 10.04 g/t Au

 SRC18-753: 8.0 metres grading 6.05 g/t Au

and 4.0 metres grading 6.77 g/t Au

 SRC18-762: 52.0 metres grading 1.61 g/t Au

o Includes 6.0 metres grading 7.16 g/t Au

 SRC18-783: 22.0 metres grading 2.96 g/t Au

o Includes 8.0 metres grading 4.66 g/t Au

Expansion Drill Holes:

 SRD18-244: 7.0 metres grading 12.46 g/t Au

o Includes 5.0 metres grading 17.22 g/t Au

 SRC18-728: 13.0 metres grading 11.60 g/t Au

o Includes 5.0 metres grading 22.37 g/t Au

 SRC18-756: 17.0 metres grading 1.39 g/t Au

and 47.0 metres grading 1.28 g/t Au

o Including: 11.0 metres grading 2.17 g/t Au

Craig MacDougall, Senior Vice President, Exploration for IAMGOLD, stated, "We continue to be very

pleased with the results of our delineation drilling programs, which confirm not only wide zones of

mineralization and locally high grades from infill holes within the existing resource, but also well

mineralized intervals beyond the original resource limits. The deposit now extends for nearly 3 kilometres

along strike, which we believe will positively impact an updated resource estimate due for completion by

year end.”

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About the Siribaya Project

The Siribaya project is wholly owned by IAMGOLD and consists of 8 contiguous exploration permits which

cover a total area of 596.5 square kilometres, located in the Kédougou-Kéniéba inlier of the West African

Craton region of western Mali along the borders with Senegal and Guinea.

The project hosts current mineral resources comprising indicated resources of 2.1 million tonnes averaging

1.90 grams of gold per tonne for 129,000 ounces and inferred resources of 19.8 million tonnes averaging

1.71 grams of gold per tonne for 1.1 million ounces (see news release dated February 12, 2018).

Gold mineralization is hosted within highly prospective, Birimian-aged metasedimentary, volcanic and

intrusive rocks proximal to the Senegal-Mali Shear Zone. At Diakha, the largest deposit discovered to date,

gold mineralization occurs within an albitized sandstone unit similar to that hosting IAMGOLD's Boto gold

deposit located in Senegal approximately 10 kilometres to the north along strike and for which a feasibility

study is nearing completion.

Next Steps

The drilling results will be used to refine the deposit model to support an updated resource estimate

expected by year end. Upon completion of the resource estimate, further drilling is anticipated in 2019 to

continue to better define and expand resources at the Diakha deposit as well as explore other identified

priority targets.

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 ("NI 43-101").

The sampling of, and assay data from, drill core and RC chips are monitored through the implementation of

a quality assurance - quality control (QA-QC) program designed to follow industry best practice. Rock chips

from Reverse Circulat ion drilling are collected at the rig site, at one metre intervals, under the direct

supervision of IAMGOLD geologists and field technicians. Samples are riffle split to obtain two 3 kg

samples. One sample is retained for reference purposes and the other sample is sent for assay.

Drill core (HQ and NQ size) samples were selected by the IAMGOLD geologists and sawn in half with a

diamond saw at the project site. Half of the core was retained at the site for reference purposes. Drill core

sample intervals are generally one metre in length.

The samples were assayed at the SGS Minerals Analytical Laboratory in Bamako, Mali, using a standard

fire assay with a 50-gram charge and an Atomic Absorption finish (FAA505). All samples returning values

greater than 10 g/t Au were re-assayed using a gravimetric finish (FAG505).

Qualified Persons

The information in this news release was prepared under the supervision of, and reviewed and verified by,

Craig MacDougall, P.Geo., Senior Vice President, Exploration for IAMGOLD. Mr. MacDougall is a Qualified

Person as defined by National Instrument 43-101.

Forward Looking Statement

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 (including, without limitation, statements regarding expected, estimated or planned gold

production, cash costs, margin expansion, capital expenditures and exploration expenditures and

statements regarding the estimation of mineral resources, exploration results, potential minera lization,

potential mineral resources and mineral reserves) are forward-looking statements. Forward-looking

statements are generally identifiable by use of the words “may”, “will”, “should”, “continue”, “expect”,

“anticipate”, “estimate”, “believe”, “intend”, “plan” or “project” or the negative of these words or other

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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, cash costs, margin expansion, capital expenditures and exploration expenditures and failure to

establish estimated mineral resources, 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 provincial 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.

About IAMGOLD

IAMGOLD ( www.iamgold.com) is a mid -tier mining company with four operating gold mines on three

continents. A solid base of strategic assets in North and South America and We st Africa is complemented

by development and exploration projects and continued assessment of accretive acquisition opportunities.

IAMGOLD is in a strong financial position with extensive management and operational expertise.

For further information please contact:

Ken Chernin, VP Investor Relations, IAMGOLD Corporation

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

Laura Young, Director, Investor Relations, IAMGOLD Corporation

Tel: (416) 933-4952 Mobile: (416) 670-3815

Martin Dumont, 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 CNW Group’s website

at www.newswire.ca. 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

http://www.iamgold.com/French/accueil/default.aspx.

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Table 1: Diakha Deposit - 2018 Diamond Drilling Assay Results (36 DDH totaling 7,098 metres)

UTM WGS84/Zone29 EOH Azimuth Dip From To Length Gold

HOLE-ID Easting Northing Elevation (m) (°) (°) (m) (m) (m) (g/t_Au)

SRD18-175-Ext 240620 1369795 155 120 108 -63 NSA

SRD18-211-Ext 240612 1369692 158 67 115 -61 NSA

SRD18-233 240660 1368671 156 201 115 -60 NSA

SRD18-234 240691 1368777 153 255 115 -60 NSA

SRD18-235 240627 1368893 153 13 115 -50 Abandoned

SRD18-235A

240627 1368890 154 280 115 -50 48 52 4 0.74

95 99 4 1.19

258 262 4 0.71

SRD18-236 240565 1368941 153 220 115 -50 72 76 4 2.43

202 206 4 4.11

SRD18-237

240699 1369043 163 300 115 -50 96 105 9 1.33

156 160 4 5.98

Includes 156 158 2 10.10

181 198 17 1.87

Includes 185 192 7 2.80

SRD18-238

240625 1369894 154 240 115 -60 49 52 3 7.36

164 168 4 0.71

202 205 3 0.75

222 226 4 1.52

SRD18-239 240641 1368961 147 252 115 -50 191 194 3 3.13

SRD18-240 240410 1369995 140 174 115 -60 34 38 4 1.21

96 99 3 1.59

SRD18-241

240668 1369174 161 220 115 -60 144 152 8 8.31

Includes 147 152 5 11.93

157 163 6 10.15

Includes 160 163 3 19.80

SRD18-242

240372 1370132 139 232 115 -60 151 167 16 0.80

179 183 4 0.91

190 193 3 1.16

SRD18-243 240890 1369948 159 170 115 -60 NSA

SRD18-244

240665 1370161 150 176 115 -60 51 54 3 1.22

72 75 3 0.76

141 144 3 0.80

168 175 7 12.46

Includes 168 173 5 17.22

SRD18-245 240433 1370161 139 154 115 -60 92 101 9 3.70

Includes 92 95 3 8.98

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111 123 12 1.10

SRD18-246 240796 1369110 170 220 115 -50 NSA

SRD18-247 240404 1369897 140 194 115 -60 86 95 9 1.69

98 104 6 1.00

SRD18-248

240691 1369596 159 340 115 -57 116 119 3 3.32

125 134 9 0.75

137 140 3 1.01

172 178 6 0.70

239 244 5 4.67

304 307 3 0.50

SRD18-249

240622 1369189 159 267 115 -60 171 174 3 0.68

219 232 13 6.05

Includes 220 225 5 10.04

252 255 3 0.74

262 267 5 0.55

SRD18-250 240715 1369475 164 13 115 -60 Abandoned

SRD18-250A

240711 1369478 161 320 115 -60 123 126 3 2.56

130 134 4 2.22

225 240 15 0.90

Includes 232 240 8 1.41

SRD18-251

240740 1369023 168 351 115 -50 41 53 12 0.86

124 134 10 5.78

SRD18-252

240444 1370429 159 160 115 -60 91 115 24 0.78

Includes 101 110 9 1.01

SRD18-253

240429 1370328 146 176 115 -62 90 98 8 0.49

140 143 3 0.63

153 156 3 12.09

SRD18-254 240737 1368806 148 200 115 -55 42 47 5 0.73

117 125 8 2.17

SRD18-255 240393 1369793 140 170 115 -60 115 127 12 1.02

SRD18-256 240739 1368872 164 330 118 -50 140 145 5 2.19

187 190 3 1.15

SRD18-257

240713 1368985 163 300 115 -60 23 27 4 1.81

152 155 3 2.19

159 167 8 1.20

SRD18-258

240722 1368923 164 300 115 -50 40 44 4 0.84

50 53 3 2.15

159 164 5 2.17

SRD18-259 240731 1368704 153 250 118 -60 76 87 11 0.93

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116 119 3 0.58

SRD18-260 240669 1368814 154 250 107 -55 96 99 3 0.58

SRD18-261

240385 1370182 139 183 115 -60 142 146 4 0.68

167 172 5 0.90

SRD18-262

240426 1370274 137 165 115 -60 90 96 6 0.68

104 112 8 0.78

Includes 110 112 2 1.05

.

SRD18-263 240455 1370369 150 165 115 -63 87 92 5 2.38

109 113 4 3.00

SRD18-264

240490 1369913 148 108 115 -58 20 29 9 1.9

Includes 20 23 3 4.12

34 38 4 1.95

 NSA – No significant assays

 Drillhole intercepts are calculated using a minimum downhole length of 3 meters, a cut-off grade of 0.5 g/t gold, and may include up to 5 metres of internal dilution.

 The true widths of intersections are interpreted to approximate the reported downhole lengths.

Table 2: Diakha Deposit - 2018 RC Drilling Assay Results (64 RC holes totaling 7,536 metres)

UTM WGS84/Zone 29 EOH Azimuth Dip From To Length Gold

Hole No Easting Northing Elevation m (°) (°) (m) (m) (m) (g/t_Au)

SRC18-724 240810 1370255 156 90 115 -58 6 19 13 0.91

Includes 14 18 4 1.58

SRC18-725 240498 1370578 152 114 115 -58 39 50 11 0.67

Includes 39 41 2 1.71

SRC18-726 240534 1370560 151 78 115 -58 11 19 8 1.11

SRC18-727 240890 1370049 158 114 115 -58 NSA

SRC18-728 240745 1368540 159 144 115 -58 44 57 13 11.60

Includes 44 49 5 22.37

62 65 3 0.48

101 106 5 1.97

SRC18-729 240572 1368717 154 140 115 -58 52 60 8 0.92

Includes 55 57 2 1.47

SRC18-730 240554 1368836 153 138 115 -58 64 75 11 1.38

Includes 64 68 4 2.75

SRC18-731 240603 1368815 154 120 115 -58 42 46 4 0.76

SRC18-732

240590 1368877 154 140 115 -52 42 45 3 1.27

57 59 2 2.17

108 118 10 0.63

Includes 113 114 1 2.09

136 140 4 1.81

0

SRC18-733 240631 1368854 154 140 115 -55 27 33 6 1.12

36 38 2 2.34

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SRC18-734 240832 1368488 159 131 115 -55 NSA

SRC18-735 240759 1368616 157 140 115 -58 40 44 4 0.85

SRC18-736 240850 1368587 155 144 115 -58 NSA

SRC18-737 240740 1368758 148 140 115 -58 NSA

SRC18-738 240749 1368583 158 140 115 -58 37 45 8 1.72

113 117 4 2.80

SRC18-739 240391 1369850 140 121 115 -58 106 112 6 2.18

115 120 5 0.94

SRC18-

738A 240392 1369851 152 60 115 -58 Abandoned

SRC18-740 240528 1369883 149 72 115 -58 18 24 6 1.04

SRC18-741 240546 1369932 150 75 115 -60 3 6 3 0.67

SRC18-742 240582 1369915 152 36 115 -60 NSA

SRC18-743 240577 1369976 151 54 115 -58 13 15 2 2.03

SRC18-744 240449 1370200 138 126 115 -58 75 81 6 2.43

104 109 5 1.62

SRC18-745 240559 1369782 152 50 150 -60 NSA

SRC18-746 240568 1369161 156 102 115 -90 NSA

SRC18-747

240837 1368816 182 126 115 -85 53 55 2 11.42

Includes 53 54 1 21.80

115 126 11 1.14

Includes 120 125 5 2.89

SRC18-748 240840 1368815 183 140 115 -58 NSA

SRC18-749 240879 1368796 184 140 115 -58 48 51 3 3.20

SRC18-750 240920 1368776 185 140 115 -58 NSA

SRC18-751 240773 1368723 148 140 105 -58 105 108 3 5.21

SRC18-752

240855 1369967 160 126 115 -58 0 3 3 1.52

22 25 3 3.67

117 118 1 11.2

SRC18-753 240934 1369930 158 120 115 -58 57 65 8 6.05

73 77 4 6.77

SRC18-754 240556 1370047 144 72 115 -58 NSA

SRC18-755 240481 1370467 156 140 115 -58 63 84 21 0.95

112 114 2 1.60

SRC18-756 240524 1370444 156 132 115 -58 10 13 3 1.08

17 34 17 1.39

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Includes 24 26 2 2.56

38 85 47 1.28

Includes 56 67 11 2.17

107 127 20 0.77

Includes 107 114 7 1.09

SRC18-757 240571 1370423 155 90 115 -58 18 27 9 0.66

SRC18-758 240832 1370300 155 72 115 -58 0 4 4 0.97

SRC18-759 240518 1370232 140 140 115 -58 22 39 17 0.92

SRC18-760 240508 1370676 149 102 115 -58 27 32 5 1.06

42 47 5 0.92

SRC18-761 240597 1370470 154 78 115 -58 12 16 4 3.23

SRC18-762

240478 1370137 139 105 115 -58 43 95 52 1.61

Includes 43 49 6 7.16

99 105 6 1.57

115 -58

SRC18-763 240775 1368404 173 0 Abandoned

SRC18-

763A 240775 1368406 164 140 115 -58 NSA

SRC18-764 240808 1368697 148 140 105 -58 NSA

SRC18-765 240472 1370252 138 126 115 -58 59 63 4 2.30

SRC18-766 240531 1370162 140 54 115 -58 0 15 15 0.63

SRC18-767 240521 1370116 140 66 115 -58 15 18 3 0.83

SRC18-768 240531 1370334 144 90 115 -58 25 28 3 1.03

37 44 7 1.30

SRC18-769

240487 1370353 150 132 115 -58 43 48 5 1.81

62 66 4 2.27

70 86 16 0.57

SRC18-770 240782 1370216 156 102 115 -58 22 29 7 0.88

SRC18-771 240491 1370022 140 140 115 -58 NSA

SRC18-772 240456 1369972 140 120 115 -58 NSA

SRC18-773 240707 1368604 157 140 115 -58 64 72 8 1.28

87 90 3 0.92

SRC18-774 240855 1368651 150 140 112 -58 NSA

SRC18-775 240789 1368567 158 112 115 -58 34 43 9 0.97

SRC18-776 240713 1368488 161 140 129 132 3 0.73

SRC18-777

115 -58 47 52 5 1.16

240756 1368471 161 140 73 77 4 1.65

85 96 11 2.43