Lega Pro Prima Divisione is the name of the third highest football league in Italy. It consists of 33 teams, divided geographically into two divisions of 16 and 17 teams for group A and B respectively. Until 2008 it was known as Serie C1.
Before the 1978-79 season there were only three leagues of professional football in Italy, the third being Serie C. In 1978, it was decided to split Serie C into Serie C1 and Serie C2. Serie C2, the fourth highest professional league in the Italian system, was also renamed in 2008 and is now called Lega Pro Seconda Divisione.
In each division, two teams are promoted to Serie B, and three teams are relegated to Lega Pro Seconda Divisione. In total, the league promotes 4 teams to Serie B and relegates 6 teams to Seconda Divisione.
The team finishing first in the regular season is directly promoted to Serie B, while teams placing 2nd to 5th are entered into a play-off semi-final for the chance of gaining the second promotional spot for that particular division.
In the play-off phase after the regular season is completed, in each division the team placed 2nd will play the team placed 5th, and the team placed 3rd will play the team placed 4th in a two-legged semi-final series with the higher classified team having home advantage in the second leg. In case of an aggregate tie score, the higher classified team is declared the winner without extra time or penalty kicks. The winning teams advance to the final in another two-leg tie with similar rules. The only difference being that if an aggregate tie exists at the end of the second match, extra time is played. If the tie persists, again the higher classified team is declared the winner and no penalty kicks are taken. The winner becomes the second team promoted for that particular division to Serie B.
The team finishing last in the regular season is directly relegated to Seconda Divisione, while teams placing 14th to 17th are entered into a relegation playoff phase called play-out. There is only one round in the play-outs. In each division the team placed 14th will play the team placed 17th, and the team placed 15th will play the team placed 16th in a double-leg series with the higher classified team having home field advantage in the second leg. In case of an aggregate tie score, the rules are exactly the same as those for the promotional semi-finals. The two winning teams remain in Prima Divisione while the two losing teams become the second and third teams relegated for that particular division.
These are the 172 clubs which took part to the 35 Serie C1 and Lega Pro Prima Divisione editions played from 1978–79 to 2013–14. The teams in bold compete in Lega Pro Prima Divisione in the current season.