| Competition: | Campionato Sammarinese di Calcio |
| Season: | 2003–04 |
| Winners: | S.S. Pennarossa |
| Prevseason: | 2002–03 |
| Nextseason: | 2004–05 |
The 2003–04 Campionato Sammarinese di Calcio season was the 19th season since its establishment. It was contested by 15 teams, and S.S. Pennarossa won the championship.
All teams play twice against the teams within their own group and once against the teams from the other group.