Denison received majority votes for the proposed merger from its shareholders but Fission failed to secure at least two-third votes from its shareholders required for the deal to move ahead.
The agreement, which was signed in June, was intended to create an equally-owned company, named Denison Energy, with an expected market value of about C$900m.
Additionally, the new company was required to consolidate Fission’s 100% owned PLS Project and Denison’s 60% owned Wheeler River Project and Denison’s interests in the Midwest, McClean Lake, Waterbury Lake, Mann Lake, and Wolly projects, as well as Denison’s strategic 22.5% ownership interest in the McClean Lake Mill.
Fission Uranium chairman and CEO Dev Randhawa earlier said: "This merger will create the uranium industry’s leading exploration and development company at a time when the sector is poised for growth.
"Denison has a strong, diversified portfolio and, with the Triple R deposit, Fission is bringing the Athabasca Basin’s largest undeveloped high-grade resource as well as a successful and award-winning technical and management team."
The two firms also terminated their respective shareholders meetings scheduled for 14 October 2015.
Denison Mines recently said that independent proxy advisory firms Institutional Shareholder Services and Glass, Lewis & Co have recommended that shareholders of both the companies vote for the plan of arrangement.
