Officers responded to multiple calls reporting a collision involving a pedestrian on West Texas Street at Fifth Street at about 9:40 a.m., according to Fairfield police.
Arriving officers found a Fairfield man lying in the street with major head trauma, police said.
The victim was taken to a trauma center where he later died, police said.
According to a preliminary investigation, the driver of a Chevrolet truck -- a 57-year-old Fairfield man -- had been turning onto West Texas Street when he struck the victim, who was walking across the street in a marked crosswalk, police said.
The driver stopped at the scene and cooperated with investigators.
Alcohol was not a factor in the crash, police said.
Anyone with information about the case is asked to contact the Fairfield police traffic unit at (707) 428-7300.