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IsoEnergy Drills 12.8% U3O8 over 9.0m in Drill Hole LE20-54 and Expands Hurricane Zone to the South with Two Strongly Mineralized Holes High-Grade Uranium Mineralization Continues to Expand and Remains Open to the South and

Drill Results

IsoEnergy Drills 12.8% U3O8 over 9.0m in Drill Hole LE20-54

and Expands Hurricane Zone to the South with Two Strongly

Mineralized Holes

High-Grade Uranium Mineralization Continues to Expand and Remains Open to the South and

Along Strike to the East for 200m

Vancouver, BC, September 17, 2020 – IsoEnergy Ltd. (“IsoEnergy” or the “Company”) (TSXV: ISO; OTCQX: ISENF) is

pleased to report additional intersections of strong radioactivity and initial chemical assays from the on -going

summer drilling program at the Hurricane zone . The Hurricane zone is a recent discovery of high- grade uranium

mineralization on the Company’s 100% owned Larocque East property (the “ Property”) in the Eastern Athabasca

Basin of Saskatchewan (Figure 1).

Highlights:

• Chemical assays from drill hole LE20 -54 returned 9.0m of 12.8% U 3O8 and 3.9% Ni from 329.5 to 338.5m,

including 4.0m of 27.1% U3O8 and 5.2% Ni from 333.0-337.0m,

• South Extension drill hole LE20 -62 intersected 4.5m of uranium mineralization (>500 CPS) from 321.0 to

325.5m, including 2.5m of very strong mineralization (>30,000 CPS),

• South Extension drill hole LE20-64 intersected 5.0m of uranium mineralization (>500 CPS) from 324.0 to

329.0m, including 4.0m of very strong mineralization (>30,000 CPS),

• Drill holes LE20-62 and LE20-64 are located on section with, and 11m and 28m (respectively) south of well

mineralized drill hole LE20-57 (previously reported),

• LE20-62 and LE20-64 extend mineralization close to the “J” fault, which remains open along- strike to the

east for 200m.

Note: Radioactivity is total gamma from drill core measured with an RS-125 hand-held spectrometer (RS-125).

Craig Parry, Chief Executive Officer commented: “I want to congratulate our Technical team on these results. The

expansion of the Hurricane zone to the south is very encouraging. Our team continues to deliver excellent drilling

results efficiently and safely.”

Steve Blower, Vice President of Exploration commented: “ Our primary objective with the summer drilling program

was to extend the zone of intense uranium mineralization to the south on the western side o f the Hurricane zone.

The results in drill holes LE20-62 and 64 have certainly done that. Importantly, it has now been extended nearly to

the “J” fault, which is open along-strike to the east for at least 200m.”

LE20-62 Radioactivity (Drill 1)

Drill hole LE20-62 is located 11m south of previously reported drill hole LE20-57, which was well mineralized (Figures

2 and 3). LE20-62 cored strongly altered Athabasca sandstone before intersecting an upper 2.5m thick interval of

weak uranium mineralization from 314.0-316.5m, followed by a 4.5m thick interval of strong mineralization from

321.0-325.5m. Included in this interval is 2.5m of intensely radioactive mineralization greater than 30,000 CPS (RS-

125), which includes a 0.5m sub-interval that is off- scale on the RS -125 hand-held scintillometer. As with all drill

holes to date at the Hurricane zone, the mineralization is located at the sub -Athabasca unconformity. Table 1

summarizes the summer 2020 drilling results to date.

LE20-64 Radioactivity (Drill 1)

Located 1 7m south of drill hole LE20 -62 (Figures 2 and 3), drill hole LE20 -64 cored strongly altered Athabasca

sandstone before intersecting an upper 3.5m thick layer of weak uranium mineralization from 316.5 -320.0m,

followed by a 5.0m thick interval of strong mineralization from 324.0 -329.0m. Included in this interval is 4.0 m of

intensely radioactive mineralization greater than 30,000 CPS (RS-125). Mineralization on this nor th-south section

(4435E) now measures at least 48m in width, and is open to the north and south. Most importantly, the summer

drilling has now expanded the zone of intense mineralization over 30m to the south, almost to the “J” fault. This

fault is parallel to the other main mineralized “H” and “I” faults, and is wide open to the east for at least 200m.

LE20-54 Assays (Drill 1)

Drilled to expand the very strong mineralization intersected in drill hole LE20 -32A (8.5m @ 19.6% U3O8) during the

winter 2020 drill program, drill hole LE20-54 intersected the sub-Athabasca unconformity approximately 7.0m north

of winter drill hole LE20-32A (Figures 2 and 4). Radioactivity in drill hole LE20-54 was previously reported. Chemical

assays have now been received and the intersection consists of 9.0m of uranium mineralization that averages 12.8%

U3O8 and 3.9% Ni from 329.5-338.5m. Included in this interval is 4.0m of 27.1% U3O8 and 5.2% Ni. Within the higher-

grade subinterval is a 0.5m section of off-scale radioactivity that contains 52.5% U3O8 and 1.6% Ni.

Other Drill Holes (Drill 2)

Five additional drill holes (LE20-58C1, 59, 60, 61 and 63A) have also been completed with Drill 2 on the eastern side

of the Hurricane zone. While all but LE20- 60 are weakly mineralized, there have been no intersections of strong

uranium mineralization in the holes completed by Drill 2 to date.

Next Steps

Expansion of the Hurricane zone mineralization to the north and south on the western side will remain the primary

focus of the program. Samples collected from the drilling completed to date are periodically shipped to the analytical

laboratory in Saskatoon. Chemical assay results generally follow within three to four weeks of the shipping dates.

The Larocque East Property and the Hurricane Zone

The 100% owned Larocque East p roperty consists of 31 mineral claims totaling 15,878ha that are not encumbered

by any royalties or other interests. Larocque East is immediately adjacent to the north end of IsoEnergy’s Geiger

property and is 35km northwest of Orano Canada’s McClean Lake uranium mine and mill.

Along with other target areas, the Pr operty covers a 15 -kilometre-long northeast extension of the Larocque Lake

conductor system; a trend of graphitic metasedimentary basement rocks that is associated with significant uranium

mineralization at the Hurricane zone, and in several occurrences on Cameco Corp . and Orano Canada Inc.’s

neighbouring property to the southwest of Larocque East. The Hurricane zone was discovered in July 2018 and was

followed up with 29 drill holes in 2019 and an additional 14 drill holes to date in 2020 . Dimensions are currently

575m along-strike, 40m wide, and up to 11m thick. The zone is open for expansion along- strike to the east and on

most sections. Mineralization is polymetallic and commonly straddles the sub-Athabasca unconformity 320 m below

surface. The best intersection to date is 33.9% U 3O8 over 8.5m in drill hole LE20 -34. Drilling at Cameco Corp.’s

Larocque Lake zone on the neighbouring property to the southwest has returned historical intersections of up to

29.9% U3O8 over 7.0m in drill hole Q22 -040. Like the nearby Geiger property, Larocque East is located adjacent to

the Wollaston -Mudjatik transition zone - a major crustal suture related to most of the uranium deposits in the

eastern Athabasca Basin. Importantly, the sandstone cover on the Property is thin, ranging between 140m and 330m

in previous drilling.

Table 1 – Summer 2020 Drilling Program Results

Hole-ID From (m) To (m) Length (m) Radioactivity1,2 Chemical Assays Orientation Location

(CPS) U3O8 (%) Ni (%) (Azm/Dip)

LE20-543 329.5 338.5 9.0 >500 12.8 3.9

180/-79 Sect 4510E incl. 333.0 337.0 4.0 >30,000 27.1 5.2

incl. 334.0 334.5 0.5 Off-scale5 52.5 1.6

LE20-553 No significant mineralization 180/-70 Sect 4785E

LE20-563 351.0 358.5 7.5 >500 Pending 180/-70 Sect 4660E

LE20-573 335.8 336.8 1.0 >500 Pending

217/-70 Sect 4435E and 343.8 353.8 10.0 >500

incl. 347.3 349.8 2.5 >40,000

incl. 347.8 348.3 0.5 Off-scale5

LE20-58 Abandoned before target 180/-69 Sect 4785E

LE20-58C15 144.0 146.5 2.5 >500 Pending 180/-71 Sect 4785E

LE20-59 342.0 347.0 5.0 >500 Pending 112/-69 Sect 4610E

Incl. 345.0 345.5 0.5 >5,000

LE20-60 No significant mineralization 000/-90 Sect 4660E

LE20-61 313.0 322.0 9.0 >500 Pending 000/-90 Sect 4660E incl. 321.5 322.0 0.5 >10,000

LE20-62 314.0 316.5 2.5 >500 Pending

000/-90 Sect 4435E and 321.0 325.5 4.5 >500

incl. 323.0 325.5 2.5 >30,000

incl. 324.5 325.0 0.5 Off-scale5

LE20-63A 329.5 330.5 1.0 >500 Pending 180/-85 Sect 4660E

LE20-64 316.5 320.0 3.5 >500 Pending

000/-90 Sect 4435E and 324.0 329.0 5.0 >500

incl. 324.5 328.5 4.0 >30,000

Notes: 1. Radioactivity is total gamma from drill core measured with an RS-125 hand-held spectrometer

2. Measurements of total gamma on drill core are an indication of uranium content, but may not correlate with chemical assay s

3. Radioactivity previously disclosed

4. Off-scale radioactivity is defined as exceeding 65,536 cps, the maximum measurable by an RS-125 spectrometer

5. LE20-58C1 is a wedged off-cut from LE20-58 at 200m

Figure 1 – Larocque East Property Map

Figure 2 – Hurricane Zone Drill Hole Location Map

Figure 3 – Vertical Cross-Section 4435E (Drill Holes LE20-62 and 64)

Figure 4 – Vertical Cross-Section 4510E (Drill Hole LE20-54)

Qualified Person Statement

The scientific and technical information contained in this news release was prepared by Andy Carmichael, P.Geo.,

IsoEnergy’s Senior Geologist, who is a “Qualified Person” (as defined in NI 43 -101 – Standards of Disclosure for

Mineral Projects). Mr. Carmichael has verified the data disclosed. All radioactivity measurements reported herein

are total gamma from an RS -125 hand -held spectrometer. As mineralized drill holes at the Hurricane zone are

oriented very steeply (-70 to -90 degrees) into a zone of mineralization that is interpreted to be horizontal, the true

thickness of the intersections is expected to be greater than or equal to 90% of the core lengths. This news release

refers to properties other than those in which the Company has an interest. Mineralization on those other properties

is not necessarily indicative of mineralization on the Company’s properties. All chemical analyses are completed for

the Company by SRC Geoanalytical Laboratories in Saskatoon, SK. For additional information regardi ng the

Company’s Larocque East Project, including its quality assurance and quality control procedures, please see the

Technical Report dated effective May 15, 2019, on the Company’s profile at www.sedar.com.

About IsoEnergy

IsoEnergy is a well-funded uranium exploration and development company with a portfolio of prospective projects

in the eastern Athabasca Basin in Saskatchewan, Canada. The Company recently discovered the high- grade

Hurricane Zone of uranium mineralization on its 100% owned Larocque East property in the Eastern Athabasca Basin.

IsoEnergy is led by a Board and Management team with a track record of success in uranium exploration,

development and operations. The Company was founded and is s upported by the team at its major shareholder,

NexGen Energy Ltd.

Craig Parry

Chief Executive Officer

IsoEnergy Ltd.

+1 778 379 3211

[email protected]

www.isoenergy.ca

Investor Relations

Kin Communications

+1 604 684 6730

[email protected]

www.isoenergy.ca

Neither the TSX Venture Exchange nor its Regulations Services Provider (as that term is defined in the policies of

the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

This news release shall not constitute an offer to sell or a solicitation of any offer to buy any securities, nor shall

there be any sale of any securities in any jurisdiction in which such offer, solicitation or sale would be unlawful. The

securities referenced herein have not been, nor will they be, registered under the United States Securities Act of

1933, as amended (the “U.S. Securities Act”), and such securities may not be offered or sold within the United States

absent registration under t he U.S. Securities Act or an applicable exemption from the registration requirements

thereunder.

Forward-Looking Information

The information contained herein contains “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. “Forward- looking information” includes, but is not limited to, statements with

respect to the activities, events or developmen ts that the Company expects or anticipates will or may occur in the

future, including, without limitation, planned exploration activities. Generally, but not always, forward -looking

information and statements can be identified by the use of words such as “ plans”, “expects”, “is expected”,