To examine the association between brace compliance and outcome. 495 (457 females) patients with late onset juvenile and adolescent idiopathic scoliosis were examined prospectively before bracing and at least 2 years after brace weaning. One spine surgeon examined all patients. 381 (353 females) answered a standardised questionnaire and 355 had radiological examination after median 24 years. Compliance was defined as brace wear > 20 h daily until weaning. Main outcomes were curve progression and surgery. At weaning, 76/389 compliers and 59/106 non-compliers had curve progression a parts per thousand yen6A degrees (OR 5.2, 95 % CI 3.3-8.2). At long-term the numbers were 68/284 and 46/71 (OR 5.8, 95 % CI 3.3-10.2), 10/284 versus 17/71 had been operated (OR 8.6, 95 % CI 3.7-19.9). We conclude that the risk for curve progression and surgery are reduced in patients with good brace compliance.