Measurements of bone mass were performed in 133 healthy Austrian women using the quantitative computed tomography technique of the lumbar spine and single photon absorptiometry of the distal forearm. The data were compared with those of 110 Austrian females with osteoporotic spine fractures. A significant difference in mean bone density of the lumbar spine was observed between normal and osteoporotic patients in every decade, whereas forearm measurements showed statistical differences in the seventh and eighth decade but not in the sixth decade. Compared to age matched controls, bone mass of osteoporotic women showed the following diminution: sixth decade: distal forearm: -12.7%, spine: -46.8%; seventh decade: distal forearm: -19.0%, spine: -36.7%, eighth decade: distal forearm: -15.4%, spine: -33.7%. It appears that postmenopausal osteoporosis involves greater loss of bone in the spine in the first decade after menopause and slows down after this period, whereas loss of forearm bone mineral density (BMD) increases with advancing age.