Denison Announces Filing of Annual Report ON Form 40-F

Denison Mines Corp.

1100 – 40 University Ave

Toronto, ON M5J 1T1

www.denisonmines.com

@DenisonMinesCo

PRESS RELEASE

DENISON ANNOUNCES FILING OF ANNUAL REPORT ON FORM 40-F

Toronto, ON – March 29, 2021 Denison Mines Corp. (“Denison” or the “Company”) (DML: TSX; DNN:

NYSE American) is pleased to announce that it has filed its 2020 annual report on Form 40-F with the U.S.

Securities and Exchange Commission ("SEC"). Denison’s Form 40-F includes its management discussion

and analysis and audited financial statements for the year ended December 31, 2020. The Form 40-F is

available on Denison's website at www.denisonmines.com, and on the SEC's website at

www.sec.gov/edgar.shtml.

Denison’s Annual Information Form has also been filed with Canadian regulatory authorities and is available

on Denison's website at www.denisonmines.com and under the Company's profile on SEDAR at

www.sedar.com.

Holders of Denison's securities may receive a free printed copy of the Company's most recent Form 40-F

and Annual Report, including the audited financial statements, by sending an email request to

[email protected], by submitting a request online at www.denisonmines.com, or by writing to

Denison Mines Corp., 1100 - 40 University Avenue, Toronto, Ontario, Canada M5J 1T1.

About Denison

Denison is a uranium exploration and development company with interests focused in the Athabasca Basin

region of northern Saskatchewan, Canada. The Company's flagship project is the 90% owned Wheeler

River Uranium Project, which is the largest undeveloped uranium project in the infrastructure rich eastern

portion of the Athabasca Basin region of northern Saskatchewan. Denison's interests in Saskatchewan also

include a 22.5% ownership interest in the McClean Lake joint venture ("MLJV"), which includes several

uranium deposits and the McClean Lake uranium mill, which is contracted to process the ore from the Cigar

Lake mine under a toll milling agreement, plus a 25.17% interest in the Midwest and Midwest A deposits,

and a 66.90% interest in the Tthe Heldeth Túé (“THT,” formerly J Zone) and Huskie deposits on the

Waterbury Lake property. Each of Midwest, Midwest A, THT and Huskie are located within 20 kilometres

of the McClean Lake mill.

Denison is engaged in mine decommissioning and environmental services through its Closed Mines group

(formerly Denison Environmental Services), which manages Denison’s Elliot Lake reclamation projects and

provides post-closure mine and maintenance services to a variety of industry and government clients.

Denison is also the manager of Uranium Participation Corporation, a publicly traded company listed on the

TSX under the symbol 'U', which invests in uranium oxide in concentrates and uranium hexafluoride.

For more information, please contact

David Cates (416) 979-1991 ext. 362

President and Chief Executive Officer

Sophia Shane (604) 689-7842

Investor Relations

Follow Denison on Twitter @DenisonMinesCo