Scoliosis with progressive deformity can develop late in life. The authors studied 200 patients older than age 50 years with back pain and recent onset of scoliosis. Seventy-one percent of patients were women, and no patient had undergone spinal surgery. The curves involved the area from T12 to L5 with the apex at L2 or L3 and did not exceed 60 degrees. Degenerative facet joint and disc disease always were present, and the curves were associated with a loss of lumbar lordosis. Forty-five patients with severe pain and neurologic deficits were studied using myelography. Indention of the column of contrast medium was seen at several levels but was most severe at the apex of the curve. It was least severe at the lumbosacral joint. The curves progressed an average of 3 degrees per year over a 5-year period in 73% of patients. Grade 3 apical rotation, a Cobb angle of 30 or more, lateral vertebral translation of 6 mm or more, and the prominence of L5 in relation to the intercrest line were important factors in predicting curve progression.