Format
Série A1
First stage
- Teams are divided into two groups of six teams.
- Double round-robin, in which all teams from one group play home-and-away games against all teams within the group.
Second stage
- Top 4 teams from each group of first stage are divided into two groups of four teams.
- Double round-robin, in which all teams from one group play home-and-away games against all teams within the group.
Third stage
- Home-and-away playoffs with the top 2 teams of each group.
The winner of the third stage is crowned the champion. The champion qualify to Campeonato Brasileiro Série C 2005 and qualify to Copa do Brasil 2006
The teams that do not participate in Brazilian Série A and Brazilian Série B will participate in Série A2.
Read more about this topic: 2005 Campeonato Catarinense