Low-grade osteomalacia, detectable only by quantitative histological measurement, was present in eight of 31 femoral heads from normocalcemia American patients having intracapsular fracture of the hip. The histological changes were of a much lower degree than those observed in overt clinical osteomalacia. Further, regional differences between the osteoid content of the proximal femur and iliac crest were demonstrated in 13 age-matched controls. In these, the osteoid content of the femoral bone averaged only 30% of that in the iliac crest.