Bone mineral content was measured in the forearms of 90 children who had recent fractures. The data were compared with those of age-matched healthy children. Bone mineral content was significantly reduced in children in whom fractures were caused by low-energy trauma. Bone mineral content in children in whom fractures were caused by high-energy trauma was also reduced, but the difference was not significant. Correction for other parameters of growth and maturation, e.g., height and weight, did not eliminate the difference in bone mineral content. These findings indicate that endogenous factors contribute to fracture not only in the elderly but also in children.