Mr. David Cates reports

DENISON REPORTS APPOINTMENT OF ELIZABETH SIDLE AS CFO AND ADDITION OF GEOFF SMITH TO EXECUTIVE TEAM

Denison Mines Corp. has appointed Elizabeth Sidle to the position of chief financial officer, in addition to her current position as vice-president, finance, and has added Geoff Smith to the position of vice-president, corporate development and commercial.

David Cates, Denison's President and Chief Executive Officer, commented, "We are proud to promote Liz Sidle to the position of Chief Financial Officer. In her prior positions with Denison, Liz has demonstrated a commitment to excellence and is a highly valued member of the executive team. We thank her for stepping in as Interim CFO, and know she will continue to excel as a leader of our finance team during this exciting time of growth for the Company.

We are also delighted to have Geoff Smith join our executive team. Geoff's extensive capital markets expertise will provide immediate value to our efforts to execute on Denison's strategic objectives, including the ongoing advancement of the Wheeler River project and other initiatives."

M s. Elizabeth Sidle - Vice President Finance & Chief Financial Officer

Ms. Sidle joined Denison in 2016, advancing to the position of Vice President Finance in 2021. Prior to joining Denison, she held various roles at Ernst & Young LLP, including serving in the firm's National Accounting and Assurance Group. Ms. Sidle is a CPA, CA and holds a Bachelor of Science from Queen's University and a Diploma in Accounting from Wilfred Laurier University. Ms. Sidle has been serving as Denison's Interim Chief Financial Officer since September 1, 2023, during a temporary medical leave of absence of the Company's previous Chief Financial Officer and since his departure from Denison in late October 2023.

Mr. Geoff Smith - Vice President Corporate Development & Commercial

Mr. Smith will be focused on supporting Denison's investor and customer engagement, the evaluation and execution of growth opportunities and financing arrangements, and the development and oversight of the Company's uranium sales and contracting strategies. Mr. Smith brings to Denison extensive experience in capital markets and the mining and resource sector, having previously served as Managing Director in the Global Mining & Metals group at Scotiabank. Mr. Smith holds an Honours Bachelor of Commerce from Queen's University and is a CFA charter holder.

About Denison

Denison is a uranium exploration and development company with interests focused in the Athabasca Basin region of northern Saskatchewan, Canada. The Company has an effective 95% interest in its flagship 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. In mid-2023, a Feasibility Study was completed for Wheeler River's Phoenix deposit as an ISR mining operation, and an update to the previously prepared PFS was completed for Wheeler River's Gryphon deposit as a conventional underground mining operation. Based on the respective studies, both deposits have the potential to be competitive with the lowest cost uranium mining operations in the world. Permitting efforts for the planned Phoenix ISR operation commenced in 2019 and have advanced significantly, with licensing in progress and a draft Environmental Impact Statement submitted for regulatory and public review in October 2022.

Denison's interests in Saskatchewan also include a 22.5% ownership interest in the McClean Lake Joint Venture, which owns several uranium deposits and the McClean Lake uranium mill, contracted to process the ore from the Cigar Lake mine under a toll milling agreement, plus a 25.17% interest in the Midwest Main and Midwest A deposits and a 67.41% interest in the THT and Huskie deposits on the Waterbury Lake property. The Midwest Main, Midwest A, THT and Huskie deposits are located within 20 kilometres of the McClean Lake mill.

Through its 50% ownership of JCU (Canada) Exploration Company, Ltd ('JCU'), Denison holds additional interests in various uranium project joint ventures in Canada, including the Millennium project (JCU, 30.099%), the Kiggavik project (JCU, 33.8118%) and Christie Lake (JCU, 34.4508%).

Denison's exploration portfolio includes further interests in properties covering approximately 285,000 hectares in the Athabasca Basin region.

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