Race Result
| GP n. 503 - 28/04/1991 - Grand Prix of San Marino Autodromo Enzo e Dino Ferrari |
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| Winner: | Ayrton Senna / McLaren-Honda - 1:35'16.750 | ||||||
| Pole Position: | Ayrton Senna / McLaren-Honda - 1:21.877 | ||||||
| Fastest Lap: | Gerhard Berger / McLaren-Honda - 1:26.531 | ||||||
| Pos | Nš | Driver | Constructor | Laps | Time/Retired | Grid | Points |
| 1 | 1 |  Ayrton Senna |
McLaren-Honda | 61 | 1:35'16.750 | 1 | 10 |
| 2 | 2 |  Gerhard Berger |
McLaren-Honda | 61 | +1.675 | 5 | 6 |
| 3 | 22 |  Jyrki Jarvi Lehto |
Dallara-Judd | 60 | + 1 lap | 16 | 4 |
| 4 | 23 |  Pierluigi Martini |
Minardi-Ferrari | 59 | + 2 laps | 9 | 3 |
| 5 | 11 | Mika Hakkinen |
Lotus-Judd | 58 | + 3 laps | 25 | 2 |
| 6 | 12 |  Julian Bailey |
Lotus-Judd | 58 | + 3 laps | 26 | 1 |
| 7 | 25 |  Thierry Boutsen |
Ligier-Lamborghini | 58 | + 3 laps | 24 | 0 |
| 8 | 8 | Mark Blundell |
Brabham-Yamaha | 58 | + 3 laps | 23 | 0 |
| 9 | 35 | Eric van de Poele |
Lambo-Lamborghini | 57 | out of fuel | 21 | 0 |
| 10 | 26 |  Erik Comas |
Ligier-Lamborghini | 57 | + 4 laps | 19 | 0 |
| 11 | 7 | Martin Brundle |
Brabham-Yamaha | 57 | + 4 laps | 18 | 0 |
| 12 | 15 | Mauricio Gugelmin |
Leyton House-Ilmor | 55 | engine | 15 | 0 |
| 13 | 19 | Roberto Moreno |
Benetton-Ford | 54 | engine | 13 | 0 |
| Ret | 4 | Stefano Modena |
Tyrrell-Honda | 41 | transmission | 6 | 0 |
| Ret | 32 | Bertrand Gachot |
Jordan-Ford | 37 | suspension | 12 | 0 |
| Ret | 33 | Andrea de Cesaris |
Jordan-Ford | 37 | gear box | 11 | 0 |
| Ret | 16 | Ivan Capelli |
Leyton House-Ilmor | 24 | spun off | 22 | 0 |
| Ret | 29 | Eric Bernard |
Lola-Ford | 17 | engine | 17 | 0 |
| Ret | 6 | Riccardo Patrese |
Williams-Renault | 17 | electrical | 2 | 0 |
| Ret | 3 |  Satoru Nakajima |
Tyrrell-Honda | 15 | transmission | 10 | 0 |
| Ret | 24 | Gianni Morbidelli |
Minardi-Ferrari | 10 | gear box | 8 | 0 |
| Ret | 28 | Jean Alesi |
Ferrari | 2 | spun off | 7 | 0 |
| Ret | 30 | Aguri Suzuki |
Lola-Ford | 2 | spun off | 20 | 0 |
| Ret | 20 | Nelson Piquet |
Benetton-Ford | 1 | spun off | 14 | 0 |
| Ret | 27 | Alain Prost |
Ferrari | 0 | spun off | 3 | 0 |
| Ret | 5 | Nigel Mansell |
Williams-Renault | 0 | collision | 4 | 0 |
| Dnq | 17 | Gabriele Tarquini |
AGS-Ford | did not qualify | 0 | ||
| Dnq | 18 | Fabrizio Barbazza |
AGS-Ford | did not qualify | 0 | ||
| Dnq | 13 |  Pedro Chaves |
Coloni-Ford | did not qualify | 0 | ||
| Dnq | 21 | Emanuele Pirro |
Dallara-Judd | did not qualify | 0 | ||
| Dnq | 14 | Olivier Grouillard |
Fondmetal-Ford | did not qualify | 0 | ||
| Dnq | 9 | Michele Alboreto |
Footwork-Porsche | did not qualify | 0 | ||
| Dnq | 10 | Alex Caffi |
Footwork-Porsche | did not qualify | 0 | ||
| Dnq | 34 | Nicola Larini |
Lambo-Lamborghini | did not qualify | 0 | ||