| «1981-04» | San Marino Grand Prix - I Gran Premio di San Marino |
| 1981-05-03 | Imola - Autodromo Internazionale Enzo e Dino Ferrari - 60 laps × 5.04 km : 302.4 km |
| Pos | Grid | Car | Driver | Constructor | Laps | Time / Gap | Interval | Points |
|---|---|---|---|---|---|---|---|---|
| 1 | 5 | 5 | Nelson Piquet | Brabham • Ford Cosworth | 60 | 1:51:23.970 | 162.873 km/h | 9 |
| 2 | 9 | 29 | Riccardo Patrese | Arrows • Ford Cosworth | 60 | +04.580 | +04.580 | 6 |
| 3 | 2 | 2 | Carlos Reutemann | Williams • Ford Cosworth | 60 | +06.340 | +01.760 | 4 |
| 4 | 13 | 6 | Hector Rebaque | Brabham • Ford Cosworth | 60 | +22.890 | +16.550 | 3 |
| 5 | 6 | 28 | Didier Pironi | Ferrari | 60 | +25.870 | +02.980 | 2 |
| 6 | 14 | 8 | Andrea de Cesaris | McLaren • Ford Cosworth | 60 | +01:06.610 | +40.740 | 1 |
| 7 | 1 | 27 | Gilles Villeneuve | Ferrari | 60 | +01:41.970 | +35.360 | |
| 8 | 3 | 16 | René Arnoux | Renault | 59 | +1 lap | ||
| 9 | 21 | 14 | Marc Surer | Ensign • Ford Cosworth | 59 | +1 lap | ||
| 10 | 7 | 7 | John Watson | McLaren • Ford Cosworth | 58 | +2 laps | ||
| 11 | 16 | 33 | Patrick Tambay | Theodore • Ford Cosworth | 58 | +2 laps | ||
| 12 | 8 | 1 | Alan Jones | Williams • Ford Cosworth | 58 | +2 laps | ||
| 13 | 24 | 10 | Slim Borgudd | ATS • Ford Cosworth | 57 | +3 laps | ||
| DNC | 18 | 25 | Jean-Pierre Jabouille | Ligier • Matra | 45 | |||
| 23 | 17 | Eliseo Salazar | March • Ford Cosworth | 38 | oil pressure | |||
| 17 | 4 | Michele Alboreto | Tyrrell • Ford Cosworth | 31 | collision | |||
| 20 | 32 | Beppe Gabbiani | Osella • Ford Cosworth | 31 | collision | |||
| 11 | 23 | Bruno Giacomelli | Alfa Romeo | 28 | collision | |||
| 19 | 3 | Eddie Cheever | Tyrrell • Ford Cosworth | 28 | collision | |||
| 12 | 22 | Mario Andretti | Alfa Romeo | 26 | gearbox | |||
| 15 | 20 | Keke Rosberg | Fittipaldi • Ford Cosworth | 14 | engine | |||
| 10 | 26 | Jacques Laffite | Ligier • Matra | 7 | collision | |||
| 4 | 15 | Alain Prost | Renault | 3 | gearbox | |||
| 22 | 31 | Miguel Angel Guerra | Osella • Ford Cosworth | 0 | accident | |||
| DNQ | 30 | Siegfried Stohr | Arrows • Ford Cosworth | |||||
| DNQ | 18 | Derek Daly | March • Ford Cosworth | |||||
| DNQ | 9 | Jan Lammers | ATS • Ford Cosworth | |||||
| DNQ | 21 | Chico Serra | Fittipaldi • Ford Cosworth | |||||
| DNQ | 36 | Derek Warwick | Toleman • Hart | |||||
| DNQ | 35 | Brian Henton | Toleman • Hart | |||||
| WDR | 11 | Elio de Angelis | Lotus • Ford Cosworth | bodywork infringement | ||||
| WDR | 12 | Nigel Mansell | Lotus • Ford Cosworth | bodywork infringement |
Fastest lap - 01:48.064 - 167.901 km/h - Gilles Villeneuve (lap 46)