Autodromo Enzo e Dino Ferrari · 3 May 1981
Nelson Piquet won the 1981 San Marino Grand Prix for Brabham from 5th on the grid, 4.58s ahead of Riccardo Patrese. Marc Surer gained the most places, from 21st on the grid to 9th.
| Pos | Team | Points Breakdown | Pts | |
|---|---|---|---|---|
| 1 | Brabham Piquet 9 + Rebaque 3 | Piquet 9 + Rebaque 3 | 12 | |
| 2 | Arrows Patrese 6 | Patrese 6 | 6 | |
| 3 | Williams Reutemann 4 + Jones 0 | Reutemann 4 + Jones 0 | 4 | |
| 4 | Ferrari Pironi 2 + Villeneuve 0 | Pironi 2 + Villeneuve 0 | 2 | |
| 5 | McLaren de Cesaris 1 + Watson 0 | de Cesaris 1 + Watson 0 | 1 | |
| 6 | Renault Arnoux 0 + Prost 0 | Arnoux 0 + Prost 0 | 0 | |
| 7 | Ensign Surer 0 | Surer 0 | 0 | |
| 8 | Theodore Tambay 0 | Tambay 0 | 0 | |
| 9 | ATS Borgudd 0 + Lammers 0 | Borgudd 0 + Lammers 0 | 0 | |
| 10 | Ligier Jabouille 0 + Laffite 0 | Jabouille 0 + Laffite 0 | 0 | |
| 11 | March Salazar 0 | Salazar 0 | 0 | |
| 12 | Tyrrell Alboreto 0 + Cheever 0 | Alboreto 0 + Cheever 0 | 0 | |
| 13 | Osella Gabbiani 0 + Guerra 0 | Gabbiani 0 + Guerra 0 | 0 | |
| 14 | Alfa Romeo Giacomelli 0 + Andretti 0 | Giacomelli 0 + Andretti 0 | 0 | |
| 15 | Fittipaldi Rosberg 0 | Rosberg 0 | 0 | |
| 16 | Team Lotus de Angelis 0 + Mansell 0 | de Angelis 0 + Mansell 0 | 0 |
| Pos | Driver | Team | Race time / Gap | Laps | Stops | Pts | |
|---|---|---|---|---|---|---|---|
| 1 | Nelson Piquet Brabham | Brabham | 1:51:23.970 | 60 | — | 9 | |
| 2 | Riccardo Patrese Arrows | Arrows | +4.580s | 60 | — | 6 | |
| 3 | Carlos Reutemann Williams | Williams | +6.340s | 60 | — | 4 | |
| 4 | Hector Rebaque Brabham | Brabham | +22.890s | 60 | — | 3 | |
| 5 | Didier Pironi Ferrari | Ferrari | +25.870s | 60 | — | 2 | |
| 6 | Andrea de Cesaris McLaren | McLaren | +1:06.610 | 60 | — | 1 | |
| 7 | Gilles Villeneuve Ferrari | Ferrari | +1:41.970 | 60 | — | — | |
| 8 | René Arnoux Renault | Renault | +1 Lap | 59 | — | — | |
| 9 | Marc Surer Ensign | Ensign | +1 Lap | 59 | — | — | |
| 10 | John Watson McLaren | McLaren | +2 Laps | 58 | — | — | |
| 11 | Patrick Tambay Theodore | Theodore | +2 Laps | 58 | — | — | |
| 12 | Alan Jones Williams | Williams | +2 Laps | 58 | — | — | |
| 13 | Slim Borgudd ATS | ATS | +3 Laps | 57 | — | — | |
| NC | Jean-Pierre Jabouille Ligier | Ligier | NC | 45 | — | — | |
| DNF | Eliseo Salazar March | March | DNF Spun off | 38 | — | — | |
| DNF | Michele Alboreto Tyrrell | Tyrrell | DNF Collision | 31 | — | — | |
| DNF | Beppe Gabbiani Osella | Osella | DNF Collision | 31 | — | — | |
| DNF | Bruno Giacomelli Alfa Romeo | Alfa Romeo | DNF Collision | 28 | — | — | |
| DNF | Eddie Cheever Tyrrell | Tyrrell | DNF Collision | 28 | — | — | |
| DNF | Mario Andretti Alfa Romeo | Alfa Romeo | DNF Gearbox | 26 | — | — | |
| DNF | Keke Rosberg Fittipaldi | Fittipaldi | DNF Engine | 14 | — | — | |
| DNF | Jacques Laffite Ligier | Ligier | DNF Suspension | 7 | — | — | |
| DNF | Alain Prost Renault | Renault | DNF Gearbox | 3 | — | — | |
| DNF | Miguel Ángel Guerra Osella | Osella | DNF Accident | 0 | — | — | |
| DNS | Jan Lammers ATS | ATS | DNS | 0 | — | — | |
| DNS | Elio de Angelis Team Lotus | Team Lotus | DNS Withdrew | 0 | — | — | |
| DNS | Nigel Mansell Team Lotus | Team Lotus | DNS Withdrew | 0 | — | — |