Seat-belt fractures of the lumbar spine in adolescents and adults are well recognised but there are few reports of these injuries in young children. We reviewed all seat-belt injuries in skeletally immature patients (Risser 0), seen at a tertiary referral centre between 1974 and 1991. There were ten cases, eight girls and two boys, with an average age of 7.5 years (3 to 13). Four distinct patterns of injury were observed, most commonly at the L2 to L4 level. Paraplegia, which is thought to be uncommon, occurred in three of our ten cases. Four children had intra-abdominal injuries requiring laparotomy. There was a delay in diagnosis either of the spinal or of the intra-abdominal injury in five cases, although all had contusion of the abdominal wall, the 'seat-belt sign'. Treatment of the fractures was conservative, by bed rest and then hyperextension casts. The incidence of this potentially devastating injury can be reduced by the optimal use of restraints, but there is often a delay in diagnosis. Our classification system may aid in the early detection and evaluation of this injury.