Authorities responded to the shooting in the 11100 block of Imperial Highway near Studebake Road at about 5:30 p.m.
Sheriff's deputies say the 55-year-old victim was shot in his mobile home at Imperial Village. He was taken to a local hospital, where he was pronounced dead.
Anyone with information was urged to call the Los Angeles County Sheriff's Department Homicide Bureau at (323) 890-5500.