Background: Bracing is the most common non-operative treatment for idiopathic adolescent scoliosis. Milwaukee brace is the best – known orthosis for this purpose. We wish to report our results with the use of this brace in idiopathic scoliosis.Methods: In a retrospective study, among 681 patients who had been treated for idiopathic scoliosis form 1994 to 2004 in two hospitals in Tehran, 335 cases had received non-operative treatment with Milwaukee brace. The radiographs of these patients were reviewed to evaluate the treatment outcome. These patients, who were 12.1 years old on average and had received no other prior treatment, had started with 23 hours per day bracing and continued in accordance with Scoliosis Research Society (SRS) protocol.Results: Milwaukee brace reduced the cobb ankle from an average of 32.8 to 30.6 degrees. The brace had no appreciable effect on curves of upper thoracic, double or triple curves. Initial thoracic kyphosis had no effect on final bracing outcome. Curve progression, while in brace, was more commonly seen in association with Risser signs "0" to "1". The best prognostic evidence in terms of control of progression was initial reduction of over 30 percent in curve magnitude in the first post-bracing visit. A reduction in curve magnitude of less than 17 percent after the first visit was associated with poor final outcome.Conclusions: Milwaukee brace can effectively reduce and control idiopathic scoliotic curves. However, good patient selection and close follow-up is mandatory.