| Race details | |
|---|---|
| Race 13 of 18 in the 1978 USAC Championship Car season | |
 | |
| Date | September 3, 1978 |
| Official name | 1978 California 500 |
| Location | Ontario Motor Speedway, Ontario, California, United States |
| Course | Permanent racing facility 2.500 mi / 4.023 km |
| Distance | 200 laps 500.000 mi / 804.672 km |
| Pole position | |
| Driver |  Tom Sneva (Team Penske) |
| Time | 199.933 mph (321.761 km/h) |
| Podium | |
| First | Al Unser (Jim Hall/Chaparral) |
| Second | Pancho Carter (Fletcher Racinf) |
| Third | Gordon Johncock (Patrick Racing) |
The 1978 California 500, the ninth running of the event, was held at the Ontario Motor Speedway in Ontario, California, on Sunday, September 3, 1978. The event was race number 13 of 18 in the 1978 USAC Championship Car season. The race was won by Al Unser, who became the only driver with win all three races in IndyCar's Triple Crown in one year.