Because of the relatively recent understanding of the untreated natural history of idiopathic scoliosis, many patients do not require treatment and are simply observed. Immature patients whose curves are between 25 degrees and 40 degrees are at high risk for further progression and should be treated with a brace. Seventy percent to 80% of the time, the patient can expect that the brace will prevent further progression. Curves in growing children greater than 40 degrees require a spinal fusion. Modern scoliosis surgery provides excellent correction of deformity and allows immediate ambulation without a cast or brace. This article reviews the diagnosis, cause, and treatment recommendations for adolescent idiopathic scoliosis.