The 1989–90 Calgary Flames season was the Flames' eighteenth season, and their tenth in Calgary. In defense of their first Stanley Cup championship, despite losing both Lanny McDonald and Jim Peplinski to retirement, the Flames remained a dominant team on the ice, finishing atop the Smythe Division and the Campbell Conference for the third consecutive year, and 2nd overall in the NHL with 99 points – two points behind the Boston Bruins.