The 2003–04 NHL season was the 87th regular season of the National Hockey League. The thirty teams played 82 games in a new format that increased divisional games from 5 to 6 per team (30 total), conference games from 3 to 4 (32 total), and decreased inter-conference games to at least one per team, with three extra games (18 in total).
The Stanley Cup winners were the Tampa Bay Lightning, who won the best of seven series 4–3 against the Calgary Flames. This was the first season since the 1969–70 season that teams would wear their dark jerseys at home. For the fourth time in eight years, the all-time record for total shutouts in a season was shattered, as 192 shutouts were recorded. The 2003–04 regular season was also the first one (excluding the lockout-shortened regular season of 1994–95) since 1967–68 in which there was neither a 50-goal scorer, nor a 100-point scorer.
This was the final season that ABC and ESPN televised NHL games. It was also the final NHL season before the 2004–05 NHL lockout, and the final season in which games could end in ties.
The 2004 playoffs were considered to be wide open with no clear favourite. All of the top teams had weaknesses. Tampa Bay and Boston were both young teams with no history of recent postseason success. Detroit, Ottawa, Colorado, and Philadelphia all had major questions in goal. New Jersey was marred by injuries to Scott Stevens and Brian Rafalski, while Vancouver was missing the suspended Todd Bertuzzi.
The first-round Eastern Conference matchups were notable for the number of heated rivalries. The Ottawa Senators met the Toronto Maple Leafs for the fourth time in five years in the always passion-filled Battle of Ontario. The Boston Bruins and Montreal Canadiens met in a resumption of the most common of all NHL playoff series, and one which the Canadiens have thoroughly dominated, including an upset win two years prior. The Philadelphia Flyers also played a hated division rival in the New Jersey Devils. The only non-rivalry was the Tampa Bay-New York Islanders series.
The West saw the resumption of the Vancouver-Calgary rivalry, which had been somewhat dormant as the Flames made the playoffs for the first time since 1996. In a less passionate but still interesting matchup, Detroit played division rival Nashville (whom they had struggled against during the regular season) in Nashville's first ever franchise visit to the playoffs. San Jose met the St. Louis Blues, while the always difficult four-five matchup saw Colorado and Dallas meet.
The Flames and the Lightning battled hard in the Stanley Cup Finals, eventually pushing the series to seven games. By game 5, the Flames took the 3–2 series lead back to Calgary, and in game six, a puck appeared to have gone into the net, which would have made the game 3–2, but the goal light did not go on, the referee did not signal that a goal had been scored, and play went on, no goal counted. Extensive replays showed the play was inconclusive. The Lightning would win the game in double overtime, and go on to win the Stanley Cup with a 2–1 win in game seven, with two goals from Ruslan Fedotenko. Brad Richards, with a team-high 25 points in the playoffs, was awarded the Conn Smythe Trophy.