2004–05 Swiss 1. Liga

The '''2004–05 Swiss 1. Liga''' was the 73rd season of this league since its creation in 1931 and, at this time, it was the third tier of the Swiss football league system. The 1. Liga was also the highest level of Swiss amateur football, despite an ever-increasing number of clubs in this league playing with professional or, more often than not, semi-professional players in their ranks and this was not just the case with the U-21 teams of the professional clubs.

Format
There were 48 teams in this division, including seven U-21 teams, which were the eldest youth teams of the professional clubs in the Super League and the Challenge League. The 1. Liga was divided into three regional groups, each with 16 teams. Within each group, the teams would play a double round-robin to decide their positions in the league. The three group winners, the runners-up, together with the two best third placed teams, then contested a play-off for the two promotion slots. The U-21 teams were not eligible for promotion and could not compete in the play-offs. The two last placed teams in each group were to be directly relegated to the 2. Liga Interregional.

Promotion play-off
Qualified for the play-offs were the first two teams from group 1; Lausanne-Sport and Serrières, from group 2; Biel-Bienne and Wangen b.O. and from group 3; Tuggen and Locarno. The two best third best teams were Étoile Carouge from group 1 and Red Star from group 3.

Qualification round
 Étoile Carouge win 3–1 on aggregate and advance to Finals.

 Lausanne-Sport win 8–3 on aggregate and advance to Finals.

 Locarno win 2–1 on aggregate and advance to Finals.

 Red Star win 6–2 on aggregate and advance to Finals.

Final round
 Locarno win 4–1 on aggregate and are promoted to 2005–06 Challenge League.

 Lausanne-Sport win 5–4 on aggregate and are promoted to 2005–06 Challenge League.

Summary
Group 1 champions were newly promoted Lausanne-Sport, they also achieved immediate promotion to the 2005–06 Challenge League. Runners-up in this group were Serrières, but they failed in their promotion attempt. Group 2 champions were Biel-Bienne and runners-up were Wangen b.O.. However, both failed in their promotion attempts. The champions of group 3, Tuggen, also missed promotion. The runners-up in group 3 were Locarno and they achieved promotion. Relegated were Malley and Stade Lausanne Ouchy from group 1, Alle and Langenthal from group 2 and from group 3 Chur and Gossau. The remaining teams in the division were to be joined in next season by Signal FC Bernex-Confignon, SC Düdingen, FC Kickers Luzern, SV Muttenz and FC Rapperswil-Jona, all of whom had won their 2. Liga Interregional groups.