Officers say the crash happened Sunday just before 12:30 am on Stephens Street at Schendel Avenue.
Investigators say a 38-year-old Modesto man was hit by a car while using the crosswalk.
Officers found him lying along the road shoulder. He was taken to the hospital with major injuries, and his condition has not been released.
The CHP believes the man was hit by a 2003-2006 silver Hyundai Elantra.
Officials say the passenger side of the vehicle may have damage from the crash.
Anyone with information about the suspect vehicle or the collision is asked to call the California Highway Patrol in Merced at 209-356-2900.