The 2009–10 Campionato Sammarinese di Calcio season was the twenty-fifth since its establishment. The season began in September 2009 and ended with the playoff final in May 2010. Tre Fiori were the defending league champions, having won their fifth Sammarinese championship the previous season.
Participating teams
Because there was no promotion or relegation, the same 15 teams that competed in the previous season competed again.
Source: fsgc.sm(in Italian) Rules for classification: 1) points; 2) head-to-head points; 3) head-to-head goal difference; 4) head-to-head goals scored; 5) goal difference; 6) number of goals scored.
Results
All teams played twice against teams within their own group and once against teams from the other group. This meant that the clubs in the eight-club group played 21 matches each while the clubs in the seven-club group played 20 matches each during the regular season.
The final took place on 31 May 2010. The winner qualified for the first qualifying round of the 2010–11 UEFA Champions League, while the runner-up qualified for the second qualifying round of the 2010–11 UEFA Europa League.