Alain Prost won the Italian Grand Prix 1985 at Autodromo Nazionale di Monza on 8 September 1985, starting from P5 on the grid. Nelson Piquet finished second for Brabham, with Ayrton Senna completing the podium for Team Lotus.
| Pos | Grid | Driver | Team | Laps | Time / Status | Pts | FL |
|---|---|---|---|---|---|---|---|
| 1 | 5 | Alain ProstPRO | McLaren | 51 | 1:17:59.451 | 9 | |
| 2 | 4 | Nelson PiquetPIQ | Brabham | 51 | +51.635 | 6 | |
| 3 | 1 | Ayrton SennaSEN | Team Lotus | 51 | +1:00.390 | 4 | |
| 4 | 9 | Marc SurerSUR | Brabham | 51 | +1:00.609 | 3 | |
| 5 | 10 | Stefan JohanssonJOH | Ferrari | 50 | +1 Lap | 2 | |
| 6 | 6 | Elio de AngelisDEA | Team Lotus | 50 | +1 Lap | 1 | |
| 7 | 8 | Patrick TambayTAM | Renault | 50 | +1 Lap | 0 | |
| 8 | 18 | Martin BrundleBRU | Tyrrell | 50 | +1 Lap | 0 | |
| 9 | 14 | Thierry BoutsenBOU | Arrows | 50 | +1 Lap | 0 | |
| 10 | 19 | Philippe StreiffSTR | Ligier | 49 | +2 Laps | 0 | |
| 11 | 3 | Nigel MansellMAN | Williams | 47 | Engine | 0 | |
| 12 | 15 | Teo FabiFAB | Toleman | 47 | +4 Laps | 0 | |
| 13 | 7 | Michele AlboretoALB | Ferrari | 45 | Engine | 0 | |
| R | 2 | Keke RosbergROS | Williams | 44 | Engine | 0 | |
| R | 20 | Jacques LaffiteLAF | Ligier | 40 | Engine | 0 | |
| R | 16 | Niki LaudaLAU | McLaren | 33 | Transmission | 0 | |
| R | 13 | Riccardo PatresePAT | Alfa Romeo | 31 | Exhaust | 0 | |
| R | 22 | Huub RothengatterROT | Osella | 26 | Engine | 0 | |
| R | 26 | Philippe AlliotALL | RAM | 19 | Turbo | 0 | |
| R | 11 | Gerhard BergerBER | Arrows | 13 | Engine | 0 | |
| R | 6 | Derek WarwickWAR | Renault | 9 | Transmission | 0 | |
| R | 25 | Alan JonesJON | Lola | 6 | Engine | 0 | |
| R | 17 | Eddie CheeverCHE | Alfa Romeo | 3 | Engine | 0 | |
| R | 24 | Kenny AchesonACH | RAM | 2 | Clutch | 0 | |
| R | 23 | Pierluigi MartiniMAR | Minardi | 0 | Fuel pump | 0 | |
| W | 0 | Piercarlo GhinzaniGHI | Toleman | 0 | Withdrew | 0 |