The 2003–04 QMJHL season was the 35th season in the history of the Quebec Major Junior Hockey League. The league continued to expand to new eastern markets, with teams relocating to Maine and Prince Edward Island. Conferences were abandoned and teams were divided into three divisions by geography. Sixteen teams played 70 games each in the schedule. The Lewiston Maineiacs became the league's second American-based team in history after the Plattsburgh Pioneers, and first to survive a full season. The P.E.I. Rocket also became the first major junior hockey team based on Prince Edward Island.