| Type: | F1 |
| Country: | Argentina |
| Grand Prix: | Buenos Aires |
| Date: | February 18 |
| Year: | 1951 |
| Official Name: | V Gran Premio del General Juan Perón y de la Ciudad de Buenos Aires |
| Race No: | Formula Libre |
| Location: | Aeroparque Costanera Buenos Aires |
| Course: | Public roads |
| Course Mi: | 2.17 |
| Course Km: | 3.50 |
| Distance Laps: | 45 |
| Distance Mi: | 90.689 |
| Distance Km: | 157.5 |
| Pole Driver: | Juan Manuel Fangio |
| Pole Team: | Mercedes |
| Pole Time: | 1:58.4 (106.42 km/h / 66.13 m/h) |
| Pole Country: | Argentina |
| Fast Driver: | Juan Manuel Fangio |
| Fast Team: | Mercedes |
| Fast Time: | 2:02.4 (102.94 km/h / 63.96 m/h) |
| Fast Country: | Argentina |
| First Driver: | José Froilán González |
| First Team: | Ferrari |
| First Country: | Argentina |
| Second Driver: | Hermann Lang |
| Second Team: | Mercedes |
| Second Country: | Germany |
| Third Driver: | Juan Manuel Fangio |
| Third Team: | Mercedes |
| Third Country: | Argentina |
The first of three 1951 Buenos Aires Grand Prix (official name: V Gran Premio del General Juan Perón y de la Ciudad de Buenos Aires) was a Formula Libre Grand Prix motor race that took place on February 18, 1951, at the Costanero Norte street circuit in Buenos Aires, Argentina.[1]
| Pos | Driver | Constructor | Laps | Time/Retired | |
|---|---|---|---|---|---|
| 1 |  José Froilán González | Ferrari 166 FL | 45 | 1:35:18.9 | |
| 2 |  Hermann Lang | Mercedes-Benz W154 | 45 | 1:35:35.3 | |
| 3 | Juan Manuel Fangio | Mercedes-Benz W154 | 45 | 1:36:10.4 | |
| 4 | Óscar Alfredo Gálvez | Ferrari 166 FL | 44 | 1:36:25.0 | |
| 5 | Alfredo Pian | Maserati 4CL | 44 | 1:36:55.0 | |
| 6 | Karl Kling | Mercedes-Benz W154 | 44 | 1:37:27.2 | |
| 7 | Pascual Puópolo | Maserati | 43 | 1:36:08.4 | |
| 8 | Hector Niemitz | Alfa Romeo | 42 | 1:35:19.0 | |
| 9 | Jorge Daponte | Maserati 4CLT | 42 | 1:37:24.8 | |
| 10 | Carlos Menditeguy | Alfa Romeo 8C 308 | 41 | 1:36:29.8 | |
| 11 | José Felix Lopes | Simca-Gordini T-15 | 38 | 1:36:01.7 | |
| 12 | Clemar Bucci | Alfa Romeo 12C-37 | 33, DNF | 1:11:20.2 | |
| Ret | Luis Alberto de Dios | Simca-Gordini T15 | 8 | DNF | |
| Ret | Roberto Miéres | Maserati | 2 | DNF | |
| Ret | Onofre Marimón | Maserati | DNS | ||
| Ret | Alberto Crespo | Maserati | DNS | ||
| Ret | Viannini | Maserati 4CL | DNS | ||
| Ret | Victorio Rosa | Maserati | DNS | ||
| Ret |  Eitel Cantoni | Maserati 4CL | DNS |