The 2003–04 NLA season was the 66th regular season of the Nationalliga A, the main professional ice hockey league in Switzerland.
Regular season
Final standings
Scoring leaders
Note: GP = Games played; G = Goals; A = Assists; Pts = Points; PIM = Penalty Minutes
Playoffs
Quarterfinals
Semifinals
Finals
Scoring leaders
Note: GP = Games played; G = Goals; A = Assists; Pts = Points; PIM = Penalty Minutes
Playout round
Teams ranked from 9 - 13 after regular season, played 2 games against each other.
Final standings
EHC Basel is relegated to Nationalliga B.
League qualification
HC Lausanne stays in Nationalliga A.