Grande Prêmio de San Marino 1981
Etapa 4 da temporada 1981 da Fórmula 1, disputada em 3 de maio de 1981.
Circuito: Autodromo Enzo e Dino Ferrari
Nelson Piquet venceu pela Brabham. Pole position: Gilles Villeneuve.
Resultado final
| Pos. | Piloto | Equipe | Grid | Voltas | Tempo | Pontos |
|---|---|---|---|---|---|---|
| 1 | Nelson Piquet | Brabham | 5 | 60 | 1:51:23.970 | 9 |
| 2 | Riccardo Patrese | Arrows | 9 | 60 | +4.580 | 6 |
| 3 | Carlos Reutemann | Williams | 2 | 60 | +6.340 | 4 |
| 4 | Hector Rebaque | Brabham | 13 | 60 | +22.890 | 3 |
| 5 | Didier Pironi | Ferrari | 6 | 60 | +25.870 | 2 |
| 6 | Andrea de Cesaris | McLaren | 14 | 60 | +1:06.610 | 1 |
| 7 | Gilles Villeneuve | Ferrari | 1 | 60 | +1:41.970 | 0 |
| 8 | René Arnoux | Renault | 3 | 59 | +1 Lap | 0 |
| 9 | Marc Surer | Ensign | 21 | 59 | +1 Lap | 0 |
| 10 | John Watson | McLaren | 7 | 58 | +2 Laps | 0 |
| 11 | Patrick Tambay | Theodore | 16 | 58 | +2 Laps | 0 |
| 12 | Alan Jones | Williams | 8 | 58 | +2 Laps | 0 |
| 13 | Slim Borgudd | ATS | 24 | 57 | +3 Laps | 0 |
| R | Jean-Pierre Jabouille | Ligier | 18 | 45 | Not classified | 0 |
| R | Eliseo Salazar | March | 23 | 38 | Spun off | 0 |
| R | Michele Alboreto | Tyrrell | 17 | 31 | Collision | 0 |
| R | Beppe Gabbiani | Osella | 20 | 31 | Collision | 0 |
| R | Bruno Giacomelli | Alfa Romeo | 11 | 28 | Collision | 0 |
| R | Eddie Cheever | Tyrrell | 19 | 28 | Collision | 0 |
| R | Mario Andretti | Alfa Romeo | 12 | 26 | Gearbox | 0 |
| R | Keke Rosberg | Fittipaldi | 15 | 14 | Engine | 0 |
| R | Jacques Laffite | Ligier | 10 | 7 | Suspension | 0 |
| R | Alain Prost | Renault | 4 | 3 | Gearbox | 0 |
| R | Miguel Ángel Guerra | Osella | 22 | 0 | Accident | 0 |
| R | Jan Lammers | ATS | – | 0 | Retired | 0 |
| W | Elio de Angelis | Team Lotus | – | 0 | Withdrew | 0 |
| W | Nigel Mansell | Team Lotus | – | 0 | Withdrew | 0 |
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