The bone mineral content (BMC) in the lumbar spine, femoral neck, and femoral shaft in 46 women ranging in age from 60 to 89 years with fractures of the femoral neck was measured by dual photon absorptiometry and compared with that of 38 healthy women in the same age group. For BMC of the lumbar spine and femoral neck there was no significant difference between the fracture group and the control group, whereas BMC of the femoral shaft was significantly reduced in the fracture group. No significant difference was found between BMC values for the 18 transcervical and 28 pertrochanteric fractures. Radiographic evidence of osteoporosis with compression fractures of vertebrae could be demonstrated in ten of the patients with femoral neck fractures. There was a significant correlation between BMC of the axial and peripheral skeleton in the patients with fractures. The Singh Index was significantly correlated with BMC of the lumbar spine but not with that of the femoral neck or shaft. It is concluded that the high incidence of femoral neck fracture with increasing age might be explained in part by a reduction in BMC, primarily cortical bone mineral, but it is likely that other factors that reduce the strength of bone or increase the tendency in older persons to fall are also of importance.