The 2009–10 Lega Pro Seconda Divisione season was the thirty-second football league season of Italian Lega Pro Seconda Divisione since its establishment in 1978, and the second since the renaming from Serie C to Lega Pro. It was divided into two phases: the regular season, played from September 2009 to May 2010, and the playoff phase from May to June 2010. The league was composed of 54 teams divided into three divisions of 18 teams each, whose teams were divided geographically. Teams played only other teams in their own division, once at home and once away for a total of 34 matches each.