In 2005, the Campeonato Brasileiro Série C was composed of five rounds.
Teams in each group played against each other in home and away games.
The two best ranked teams of each group advanced to the second round, where they were paired 2-by-2 and played home and away games.
The four eventual finalists were put in a single group, and played against each other in home and away games.
América (RN) and Remo (PA) were promoted to the Série B, beating Novo Hamburgo (RS) and Ipatinga (MG).