The Serie B championship has had different formats over the years, maintaining the division of the participating teams into several groups according to geographical distribution until the 2017/18 season. The number of groups over the years has varied from two (from 1989/90 to 1995/96) to six (2005/06). Promotion to
Serie A or Serie A2 (from 2003 to 2011) was assigned either to the winners of the individual groups or via special play-offs. In the years in which Serie B was the third tier of Italian football, the league format consisted of four or five groups of 12 teams each on average. The first in each group were promoted to Serie A2, while the bottom three teams were relegated to
Serie C, the organization of which was entrusted to the Regional Committees of the
Italian Football Federation (FIGC). For the 2010/11 season, the format had been changed in view of the dissolution of the division: 33 teams divided into three groups of 12 (group A), 11 (group B) and 10 teams (group C), with 14 promotions divided as follows: the first 4 of each group, plus two winners of the play-offs between fifth and sixth of groups A and B. Only 3 teams were relegated to
Serie C, i.e. the bottom of each group. From the 2013/14 season to the 2017/18 season, the teams were divided into 4 groups according to geographical distribution. The first team in each group (4 teams in total) were promoted to
Serie A and the bottom two were relegated to
Serie C. In the 2018/19 and 2019/20 seasons, there were 12 participating teams playing in one group with round-trip matches for a total of 22 matchdays. The top two teams are promoted to
Serie A. The teams in the last two positions are relegated directly to
Serie C. The teams in ninth and tenth place play a play-out, on neutral ground in a single match, against the two teams in
Serie C who lost the promotion play-offs, for another two places in Serie B. In the 2020/21 season, the number of participating teams was increased to 14, while the total number of matchdays rose to 26. The number of teams promoted to
Serie A remained at two, while the bottom 4 were relegated to
Serie C. == Clubs ==