The company said commercial production marks a transition in the accounting treatment for costs incurred at the facility.
Cameco met all of the rules for commercial production during May, including cycle time and process conditions.
From 1 May, the entire production costs, including depreciation, will be charged to inventory and recognized in cost of sales as the product was sold.
Mining at Cigar Lake started in March 2014, with the initial packaged uranium concentrate available in October 2014.
The annual production of the facility is expected to be in the range of 6 million to 8 million packaged pounds in 2015.
Cameco expects Cigar Lake to increase to its full annual production rate of 18 million pounds by 2018.
Cameco operates and owns 50.025% stake in the Cigar Lake mine and Areva owns 37.1% interest.
Idemitsu Canada Resources and Tepco Resources own 7.875% and 5% stakes respectively.
Cameco’s uranium products are used to generate energy in nuclear power facilities across the world. The company also explores for uranium in the Americas, Australia and Asia.
