Cameco Corporation is the world's largest publicly traded uranium company, based in Saskatoon, Saskatchewan. In 2015, it was the world's second largest uranium producer, accounting for 18% of world production.

"Cameco - Canadian Mining and Energy Corporation" was formed in 1988 by the merger and privatization of two crown corporations: the federally owned Eldorado Nuclear Limited (known previously as Eldorado Mining and Refining Limited) and Saskatchewan-based Saskatchewan Mining Development Corporation (SMDC). The name was later shortened to "Cameco Corporation".

The new company was initially owned 62% by the provincial government and 38% by the federal government. The initial public offering (IPO) for 20% of the company was conducted in July, 1991. Government ownership of the company decreased over the next eleven years, with full privatization occurring in February, 2002.

In 1996, Cameco acquired Power Resources Inc., the largest uranium producer in the United States. This was followed in 1998 by the acquisition of Canadian-based Uranerz Exploration and Mining Limited and Uranerz U.S.A., Inc.

In 2012, it acquired a nuclear fuel intermediary Nukem Energy.

Cameco operates uranium mines in North America and Kazakhstan, including McArthur River-Key Lake, the world's largest uranium producer, and Cigar Lake, the world's highest grade uranium mine, both in Saskatchewan. Other operations in Saskatchewan include a mine and mill at Rabbit Lake, currently in care and maintenance.

In the United States, Cameco operates uranium mines in the states of Nebraska and Wyoming through its US subsidiary Cameco Resources Inc. Cameco Resources was formed in 2007 through a restructuring of two wholly owned subsidiaries, Power Resources Inc. (Wyoming) and Crow Butte Resources, Inc. (Nebraska).

In the province of Ontario, Cameco operates a uranium refinery in Blind River and a uranium conversion facility in Port Hope, which has faced opposition from some community groups. Through the Bruce Power Limited Partnership (BPLP), Cameco also participates in nuclear power generation in the province.

In 2004, Cameco spun off its gold mining operations in Kyrgyzstan, Mongolia and the USA to a newly formed public company, Centerra Gold. Cameco divested its remaining interest in Centerra on December 30, 2009.

Current (2014) members of the board of directors of Cameco Corporation are:

In January 2011, Cameco participated in the clean up of a ship-board uranium concentrate spill on the MCP Altona that had occurred on December 23, 2010.

In 2011, Cameco signed an agreement with Talvivaara Mining Company whereby Cameco would pay US$60 million to construct a uranium extraction circuit at the Talvivaara nickel-zinc mine in Sotkamo. Talvivaara would then pay back the initial construction costs in the form of uranium concentrate; once the initial costs were paid Cameco would continue to purchase the uranium concentrate at a pricing formula based on market price on the day of delivery.