The reversibility of steroid-induced osteoporosis, a major complication of Cushing syndrome and long-term use of exogenous corticosteroids, is not well documented. We measured the bone mineral density of lumbar vertebras and the femoral neck by dual-photon absorptiometry and determined the biochemical variables of bone turnover in two patients successfully treated for Cushing syndrome who were followed for the next 24 months. Our data are the first to show marked increases in bone density (up to 20%) during the recovery period. The accompanying biochemical changes, particularly the marked increase in serum osteocalcin levels, confirm that enhanced bone formation occurred during the recovery phase. These findings suggest that steroid-induced osteoporosis can be reversed at least in young persons.