Saskatchewan-based Cameco says the deal extending through 2033 is its first with the Balkan nation.
Under the terms, Cameco will deliver the equivalent of about 5.7 million pounds of uranium, sufficient volume to power the Kozloduy 5 Reactor at the country's only nuclear generating station.
"We are very pleased to add another market to Cameco's global commercial portfolio, and to expand our contributions to countries like Bulgaria that are seeking to enhance their energy security while affirming their commitment to carbon-free nuclear power in achieving their climate goals," Cameco president and CEO Tim Gitzel stated in a news release.
Nuclear power accounts for more than one-third of Bulgaria's electricity supply. Kozloduy 5 is one of two reactors operating in the country.
Toronto-listed Cameco shares fell 0.32 per cent to $34.26 as at 3:32 p.m. ET on Thursday.
Jeff Lagerquist is a senior reporter at Yahoo Finance Canada. Follow him on Twitter @jefflagerquist.