The nature of injuries to 2684 car occupants involved in 1055 car accidents were analysed. Less than 1% front-seat occupants were children, compared with 25% of rear-seat passengers. Nearly all (97%) rear-seat passengers were unrestrained. Type of impact was generally similar for front-seat as for back-seat occupants, except for rollover impacts, which were commoner among rear-seat passengers. Injury severity distribution was similar for front-seat as for rear-seat occupants. Except for minor-to-moderate neck injuries, which were the result of deceleration, most injuries to rear-seat passengers were due to contact with the front seat, with glazing materials, or with other parts of the car. The use of car restraints by rear-seat passengers should reduce the incidence and severity of injuries.