The 2009–10 Lega Pro Prima Divisione season will be the thirty-second football league season of Italian Lega Pro Prima Divisione since its establishment in 1978, and the second since the renaming from Serie C to Lega Pro.
It will be divided into two phases: the regular season, played from 23 August 2009 to May 2010, and the playoff phase from May to June 2010.
The league will also be composed of 36 teams divided into two divisions of 18 teams each, whose teams will be divided geographically. Teams will play only other teams in their own division, once at home and once away for a total of 34 matches each.
Teams finishing first in the regular season, plus one team winning the playoff round from each division will be promoted to Serie B; teams finishing last in the regular season, plus two relegation playoff losers from each division will be relegated to Lega Pro Seconda Divisione. In all, four teams will be promoted to Serie B, and six teams will be relegated to Lega Pro Seconda Divisione.
The league was to feature four teams relegated from Serie B in 2008-09; Rimini, Pisa, Avellino, and Treviso. On July 9, the Covisoc (Commissione di Vigilanza sulle Società Calcistiche, Vigilancy Commission on Football Clubs) organization announced that Pisa, Avellino, and Treviso did not pass the financial requirements in order to be admitted to the league. The clubs were allowed to appeal the decision until July 11. On July 10 Pisa announced they were not appealing the exclusion from the league due to their failure to meet the financial requirements. The next day, Treviso and Avellino failed to appeal the exclusion as well.