A follow-up study of the bone mineral densities (BMD) of 22 female subjects with idiopathic scoliosis was performed using dual-photon absorptiometry at an average follow-up period of 30.8 months. Compared to the initial scans, statistically significant increases in lumbar spine and femoral neck BMD were observed. When compared to normal subjects, approximately half of the scoliotic subjects were markedly osteoporotic, having BMD measurements at least two standard deviations below the expected value. Scoliotic curvature data could not be correlated with the BMD data. The observed osteoporosis is not transient and appears characteristic of idiopathic scoliosis.