Using miniature roentgenograms of the abdomen to estimate vertebral osteoporosis and the photon absorption (125I) method applied to the distal end of the radius to estimate bone mineral in a normal working population including four ethnicities, it was found that age, sex, and skin color in decreasing order had the greatest effect on bone mineral; that mineral content peaked at thirty-five in both men and women and fell abruptly after forty-five in women and after sixty-five years in men; and that 33.3 per cent of the women and 11.9 per cent of the men had slight osteoporosis. Although there was in general an inverse relationship between bone mineral and osteoporosis, it was concluded that the photon absorption method as applied in this study is not a useful technique for the early detection of osteoporosis.