Investigators said the boy was hit by a pick-up truck.
One witness described the suspect's vehicle as a tan, four-door Chevy Silverado 2500.
He said the hit-and-run accident was shocking to see.
"He just hit a little boy, like an 8-year-old boy and just took off," Alex Jimenez said. "He never stopped, he just hit him. He just straight out ran him over."
The boy was transported to Loma Linda University Medical Center.
His condition has not been released.
Anyone with information is urged to call the San Bernardino County Sheriff's Department at 1-800-78-CRIME.