The 2005 12 Hours of Sebring was the 53rd running of this event, and took place on March 19, 2005. The race was sponsored by Mobil 1 and was the opening race of the 2005 American Le Mans Series season run by IMSA.
Class winners in bold. Cars failing to complete 70% of winner's distance marked as Not Classified (NC).
| Pos | Class | No | Team | Drivers | Chassis | Tyre | Laps | 
|---|---|---|---|---|---|---|---|
| Engine | |||||||
| 1 | LMP1 | 1 |   |   | Audi R8 | M | 361 | 
| Audi 3.6 L Turbo V8 | |||||||
| 2 | LMP1 | 2 |   |   | Audi R8 | M | 361 | 
| Audi 3.6 L Turbo V8 | |||||||
| 3 | LMP1 | 16 |   |   | MG-Lola EX257 | M | 341 | 
| MG (AER) XP20 2.0 L Turbo I4 | |||||||
| 4 | GT1 | 57 |   |   | Aston Martin DBR9 | M | 338 | 
| Aston Martin 6.0 L V12 | |||||||
| 5 | GT1 | 3 |   |   | Chevrolet Corvette C6.R | M | 337 | 
| Chevrolet LS7R 7.0 L V8 | |||||||
| 6 | GT1 | 4 |   |   | Chevrolet Corvette C6.R | M | 323 | 
| Chevrolet LS7R 7.0 L V8 | |||||||
| 7 | GT2 | 31 |   |   | Porsche 911 GT3-RSR | M | 321 | 
| Porsche 3.6 L Flat-6 | |||||||
| 8 | GT1 | 63 |   |   | Saleen S7-R | M | 318 | 
| Ford 7.0 L V8 | |||||||
| 9 | GT1 | 35 |   |   | Maserati MC12 | P | 316 | 
| Maserati 6.0 L V12 | |||||||
| 10 | GT1 | 5 |   |   | Chevrolet Corvette C5-R | Y | 315 | 
| Chevrolet LS7R 7.0 L V8 | |||||||
| 11 | GT2 | 79 |   |   | Porsche 911 GT3-RSR | P | 314 | 
| Porsche 3.6 L Flat-6 | |||||||
| 12 | LMP2 | 10 |   |   | Courage C65 | K | 311 | 
| AER P07 2.0 L Turbo I4 | |||||||
| 13 | GT2 | 45 |   |   | Porsche 911 GT3-RSR | M | 311 | 
| Porsche 3.6 L Flat-6 | |||||||
| 14 | GT1 | 71 |   |   | Dodge Viper GTS-R | P | 310 | 
| Dodge 8.0 L V10 | |||||||
| 15 | GT1 | 58 |   |   | Aston Martin DBR9 | M | 303 | 
| Aston Martin 6.0 L V12 | |||||||
| 16 | GT2 | 66 |   |   | Porsche 911 GT3-RSR | M | 297 | 
| Porsche 3.6 L Flat-6 | |||||||
| 17 | GT2 | 96 |   |   | Porsche 911 GT3-RSR | D | 278 | 
| Porsche 3.6 L Flat-6 | |||||||
| 18 | GT2 | 34 |   |   | Porsche 911 GT3-R | P | 275 | 
| Porsche 3.6 L Flat-6 | |||||||
| 19 DNF  | LMP1 | 20 |   |   | MG-Lola EX257 | M | 264 | 
| MG (AER) XP20 2.0L Turbo I4 | |||||||
| 20 NC  | GT2 | 51 |   |   | Panoz Esperante GT-LM | P | 239 | 
| Ford (Elan) 5.0 L V8 | |||||||
| 21 DNF  | LMP2 | 27 |   |   | Courage C65 | P | 238 | 
| Judd XV675 3.4 L V8 | |||||||
| 22 DNF  | GT2 | 43 |   |   | Porsche 911 GT3-RSR | Y | 207 | 
| Porsche 3.6 L Flat-6 | |||||||
| 23 DNF  | LMP1 | 12 |   |   | Riley & Scott Mk III C | D | 202 | 
| Elan 6L8 6.0 L V8 | |||||||
| 24 DNF  | LMP2 | 37 |   |   | Lola B05/40 | G | 166 | 
| AER P07 2.0 L Turbo I4 | |||||||
| 25 DNF  | GT1 | 83 |   |   | Saleen S7-R | P | 159 | 
| Ford 7.0 L V8 | |||||||
| 26 DNF  | GT2 | 41 |   |   | TVR Tuscan T400R | D | 157 | 
| TVR Speed Six 4.0 L I6 | |||||||
| 27 DNF  | GT1 | 86 |   |   | Ferrari 550-GTS Maranello | M | 155 | 
| Ferrari 5.9 L V12 | |||||||
| 28 DNF  | GT2 | 40 |   |   | TVR Tuscan T400R | D | 136 | 
| TVR Speed Six 4.0 L I6 | |||||||
| 29 DNF  | LMP1 | 88 |   |   | Dallara SP1 | M | 130 | 
| Nissan 3.6 L Turbo V8 | |||||||
| 30 DNF  | GT2 | 50 |   |   | Panoz Esperante GT-LM | P | 121 | 
| Ford (Elan) 5.0 L V8 | |||||||
| 31 DNF  | GT2 | 48 |   |   | Spyker C8 Spyder GT2-R | D | 121 | 
| Audi (Mader) 3.8 L V8 | |||||||
| 32 DNF  | GT2 | 23 |   |   | Porsche 911 GT3-RSR | M | 98 | 
| Porsche 3.6 L Flat-6 | |||||||
| 33 DNF  | LMP2 | 30 |   |   | Lola B2K/40 | P | 62 | 
| Judd XV675 3.4 L V8 | |||||||
| 34 DNF  | GT2 | 24 |   |   | Porsche 911 GT3-RSR | M | 62 | 
| Porsche 3.6 L Flat-6 | |||||||
| 35 DNF  | GT2 | 44 |   |   | Porsche 911 GT3-RSR | M | 46 | 
| Porsche 3.6 L Flat-6 | |||||||
| 36 DNF  | GT2 | 67 |   |   | Porsche 911 GT3-RSR | M | 21 | 
| Porsche 3.6 L Flat-6 | |||||||
| 37 DNF  | GT2 | 47 |   |   | Spyker C8 Spyder GT2-R | D | 18 | 
| Audi (Mader) 3.8 L V8 | |||||||
| 38 DNF  | LMP2 | 15 |   |   | Lola B05/40 | P | 11 | 
| Nicholson-McLaren 3.3 L V8 |