We studied the bone mineral and calcium (Ca) status of 17 children who suffered an accidental fracture in 1980. These children were matched by age and sex to a nonfractured control group. Blood was drawn for serum Ca, phosphorus, magnesium, 25-hydroxycholecalciferol ( calcidiol ), alkaline phosphatase, and albumin. Bone mineral content (BMC) was evaluated by photon absorptiometry. There were no differences in serum values between the two groups. Twelve (71%) of the 17 children in the fracture group had a lower BMC than their matched controls. The BMC of the fracture group was lower than their controls, 0.423 +/- 0.042 v 0.461 +/- 0.037 g/cm. Four of the 15 in the fracture group ingested less than 60% of the recommended dietary allowance (RDA) for Ca and P (800 mg/day), while all the controls were ingesting at least 60% of the RDA. Four children of the fracture group who were ingesting less Ca and P than those of the control group also had low BMC.