The 1981 San Marino Grand Prix was Round 4 of the 1981 FIA Formula 1 World Championship. The event was held in Imola, Italy on Sunday, 3 May 1981. Gilles Villeneuve started on pole position for Ferrari and Nelson Piquet was the race winner in the Brabham Ford.
1981 San Marino Grand Prix Race Result
| Pos. | No. | Driver | Nationality | Team | Tyre | Laps | Time/Retired | Race Time | Gap | Interval | Best Lap | Lap | Speed | Started | Points |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 5 | Nelson Piquet | Brazil | Brabham Ford | Michelin | 60 | 1:51:23.970 | 1:51:23.970 | - | - | 1:48.830 | 8 | 162.870 | 5 | 9 |
| 2 | 29 | Riccardo Patrese | Italy | Arrows Ford | Michelin | 60 | +4.580 | 1:51:28.550 | +4.580 | +4.580 | 1:49.416 | 10 | 162.760 | 9 | 6 |
| 3 | 2 | Carlos Reutemann | Argentina | Williams Ford | Michelin | 60 | +6.340 | 1:51:30.310 | +6.340 | +1.760 | 1:49.753 | 51 | 162.720 | 2 | 4 |
| 4 | 6 | Hector Rebaque | Mexico | Brabham Ford | Michelin | 60 | +22.890 | 1:51:46.860 | +22.890 | +16.550 | 1:49.182 | 45 | 162.320 | 13 | 3 |
| 5 | 28 | Didier Pironi | France | Ferrari | Michelin | 60 | +25.870 | 1:51:49.840 | +25.870 | +2.980 | 1:49.170 | 10 | 162.250 | 6 | 2 |
| 6 | 8 | Andrea de Cesaris | Italy | McLaren Ford | Michelin | 60 | +1:06.61 | 1:52:30.580 | +1:06.610 | +40.740 | 1:50.260 | 34 | 161.270 | 14 | 1 |
| 7 | 27 | Gilles Villeneuve | Canada | Ferrari | Michelin | 60 | +1:41.97 | 1:53:05.940 | +1:41.970 | +35.360 | 1:48.064 | 46 | 160.430 | 1 | |
| 8 | 16 | René Arnoux | France | Renault | Michelin | 59 | +1 lap | 1:51:38.650 | 1 lap | 1 lap | 1:50.103 | 14 | 159.810 | 3 | |
| 9 | 14 | Marc Surer | Switzerland | Ensign Ford | Michelin | 59 | +1 lap | 1:52:57.650 | 1 lap | +1:19.000 | 1:50.116 | 49 | 157.950 | 21 | |
| 10 | 7 | John Watson | Great Britain | McLaren Ford | Michelin | 58 | +2 laps | 1:51:29.200 | 2 laps | 1 lap | 1:48.377 | 47 | 157.320 | 7 | |
| 11 | 33 | Patrick Tambay | France | Theodore Ford | Michelin | 58 | +2 laps | 1:51:29.750 | 2 laps | +0.550 | 1:49.568 | 48 | 157.310 | 16 | |
| 12 | 1 | Alan Jones | Australia | Williams Ford | Michelin | 58 | +2 laps | 1:53:22.890 | 2 laps | +1:53.140 | 1:49.755 | 34 | 154.690 | 8 | |
| 13 | 10 | Slim Borgudd | Sweden | ATS Ford | Michelin | 57 | +3 laps | 1:51:31.360 | 3 laps | 1 lap | 1:50.884 | 45 | 154.560 | 24 | |
| NC | 25 | Jean Pierre Jabouille | France | Ligier Matra | Michelin | 45 | +15 laps | 1:51:21.310 | 1:51.496 | 33 | 122.200 | 18 | |||
| DNF | 17 | Eliseo Salazar | Chile | March Ford | Michelin | 38 | Spun Off | 1:13:26.800 | 1:51.830 | 13 | 156.460 | 23 | |||
| DNF | 4 | Michele Alboreto | Italy | Tyrrell Ford | Michelin | 31 | Collision | 58:32.023 | 1:50.950 | 9 | 160.153 | 17 | |||
| DNF | 32 | Beppe Gabbiani | Italy | Osella Hart | Michelin | 31 | Collision | 58:32.545 | 1:50.985 | 15 | 160.130 | 20 | |||
| DNF | 23 | Bruno Giacomelli | Italy | Alfa Romeo | Michelin | 28 | Collision | 52:40.720 | 1:51.234 | 10 | 160.732 | 11 | |||
| DNF | 3 | Eddie Cheever | United States | Tyrrell Ford | Michelin | 28 | Collision | 52:41.503 | 1:50.591 | 9 | 160.693 | 19 | |||
| DNF | 22 | Mario Andretti | United States | Alfa Romeo | Michelin | 26 | Gearbox | 51:16.747 | 1:51.110 | 13 | 153.325 | 12 | |||
| DNF | 20 | Keke Rosberg | Finland | Fittipaldi Ford | Avon | 14 | Engine | 27:33.034 | 1:53.865 | 14 | 153.666 | 15 | |||
| DNF | 26 | Jacques Laffite | France | Ligier Matra | Michelin | 7 | Suspension | 11:22.792 | 1:50.343 | 6 | 186.012 | 10 | |||
| DNF | 15 | Alain Prost | France | Renault | Michelin | 3 | Gearbox | 6:14.882 | 1:57.396 | 2 | 145.197 | 4 | |||
| DNF | 31 | Miguel Angel Guerra | Argentina | Osella Hart | Michelin | Accident | 22 | ||||||||
| DNQ | 20 | Siegfried Stohr | Italy | Arrows Ford | Michelin | ||||||||||
| DNQ | 18 | Derek Daly | Ireland | March Ford | Michelin | ||||||||||
| DNQ | 9 | Jan Lammers | Netherlands | ATS Ford | Michelin | ||||||||||
| DNQ | 21 | Chico Serra | Brazil | Fittipaldi Ford | Avon | ||||||||||
| DNQ | 36 | Derek Warwick | Great Britain | Toleman Hart | Pirelli | ||||||||||
| DNQ | 35 | Brian Henton | Great Britain | Toleman Hart | Pirelli |