To date no knowledge of the incidence of scoliosis in adults and its relationship to low-back pain is available. In order to arrive at an understanding of low-back pain in adult scoliosis, a study of 5000 intravenous pyelograms was performed. The incidence of lumbar and thoracolumbar curves was 2.9%. One hundred and fifty-nine of the 189 patients found to have scoliosis were contacted. The incidence of back pain was 59% (similar to that in the general population). Back pain was subdivided into mild (44%), moderate (49%), or severe (7%). The curve was subdivided into three categories: 10-24 degrees, 25-44 degrees, and 45+ degrees. Of the 82 idiopathic curves with pain, 64 were in group 1, 15 in group 2, and 3 in group 3. Forty-three percent had mild pain, 50% had moderate pain, and 7% had severe pain. As the degree of curvature increased, the severity of pain increased, especially for curves of more than 45 degrees. Patients without back pain tended to have smaller curves. the presence of facet sclerosis correlated with a history of pain in 64%. There was a high correlation between radiologic changes at the curve apex and pain. Age bore no relationship to the incidence of pain.