It happened just before 9:30 on Saturday night on North Bear Creek drive near Pira Drive.
Detectives say 42-year-old Sabian Martinez overturned his vehicle, then went straight down the nearby creek.
Officers found the car partially submerged in water, and pulled Martinez out of the car.
First responders tried to save his life, but he died at the scene.
Merced police are still figuring out what caused Martinez to crash into the creek.