The 2004–05 QMJHL season was the 36th season in the history of the Quebec Major Junior Hockey League. The QMJHL inaugurates the Guy Carbonneau Trophy, awarded to the league's "Best Defensive Forward," and the Kevin Lowe Trophy, awarded to the league's "Best Defensive Defenceman." Sixteen teams played 70 games each in the schedule.
Sidney Crosby was the league's top scorer, regular season MVP, Playoff leading scorer, and playoff MVP. Crosby helped lead the Rimouski Océanic on a 28-game unbeaten streak to close out the season, and finishing first overall in the regular season winning their second Jean Rougeau Trophy. Rimouski extended its unbeaten streak to 35 games in the playoffs, and lost only once, en route to winning their second President's Cup, defeating the Halifax Mooseheads in the finals.
The 2004 ADT Canada-Russia Challenge was hosted by Quebec City and Montreal. On November 21, 2004, the Russian Selects defeated the QMJHL All-stars 4–3 in a shootout (2–0) at the Colisée Pepsi. On November 22, 2004, the Russian Selects defeated the QMJHL All-stars 4–3 in a shootout (3–0) at the Bell Centre. Since the tournament began in 2003, the Russian Selects had an all-time record of 3 wins and 1 loss versus the QMJHL All-stars.
Playoffs
Each regular season division winner received a first round bye, and ranked 1st, 2nd, and 3rd overall. Remaining teams were ranked 4th to 13th, regardless of division.
Sidney Crosby was the leading scorer of the playoffs with 31 points (14 goals, 17 assists).