This study examined the frequency of spine and abdominal injuries to motor vehicle occupant crash victims, the relationship between the two types of injuries, and the association with restraint use. There were 303 motor vehicle occupants treated at a regional trauma center for spine and/or abdominal injuries over a 5-year period. Patients with Chance-type fractures of the lumbar spine were much more likely to be rear seat passengers and to be using a lap belt than were patients with other types of spinal injuries. Similarly, patients with hollow viscus injuries were more likely to be rear seat passengers and to be lap belted than were patients with injuries to the spleen, liver, pancreas, or kidneys. Nearly two thirds of the lumbar Chance-type fractures were associated with hollow viscus injuries, including six of seven children. This increased risk of Chance-type fractures and hollow viscus injuries was associated with increased use of lap-belt seat restraints in the population.