The study describes trauma and injury patterns related to various modes of restraint use. The sample consisted of under four year olds evaluated and treated in emergency rooms after involvement in a motor vehicle accident. Most CSS and seat-belted children, if injured, sustained minor contusions, abrasions or lacerations although there were some seriously injured. Injury among children in properly used CSS's was primarily the result of passive mechanisms of injury (e.g., flying glass, intrusion). Improper use also contributed to injury among CSS restrained children. Seat belted injured children primarily were injured due to hitting against the dashboard or the back of the front seat.