Incidence of back pain in a referred and followed group of 197 adults with idiopathic scoliosis and in a comparable control group of 180 adults without known spinal deformity was the same. Severity of pain, however, was greater in scoliotic patients. The clinical course of back pain in adults without spinal deformity and in scoliotics was different: 64% improvement in adults without scoliosis versus 83% persistence and progression in adults with scoliosis. Fifty-one percent of adult scoliotics (101 patients) had significant pain. Pain increased with age and degree of scoliotic curvature (P less than 0.0005). Patients with major lumbar curves had more pain. Major complaint was frequently below major deformity. Compensatory lumbosacral fractional curves were most painful and disabling. Pain comes mainly from concavity of curves and includes discogenic, facet joint, and radicular origins. Surgery significantly reduced pain (P less than 0.0001); conservative therapy did not. Eighty-three percent of surgical patients had sufficient pain relief to make surgery worthwhile at five years average follow-up.