The results in thrity-six adolescent idiopathic scoliosis patients(thirty-nine curves) who have been treated with the Boston brace are reported. The average follow-up was two years and three months(range, one year to four years ten months). Before treatment, all the patients had a curve that measured 20 to 35 degrees; 26 patients were in Risser sign of zero or 1, 10 patients in Risser sign 2 to 4. Although the magnitude of the curve was generally reduced about 40 percent by the initial application of the brace, a gradual loss of this initial correction was observed both during active treatment and after the wearing of the brace. Although eleven(28.2 percent) of the curves had progressed more than 5 degrees at follow up. Sixty-seven percent of the thoracic curve, 33.3 percent of the thoracolumbar, 27.8 percent of the lumbar curve had progression of more than 5 degrees. Twelve patients wore the brace for sixteen hours a day, 19 patients wore for 16 to 20 hours a day and 5 patients wore more than 20 hours a day. 41.7 percent of sixteen hours bracing, 15,8 percent of 16 to 20 hours bracing and 60 percent of 20 hours bracing had progression of more than 5 degrees. Our finding indicates that the Boston brace prevents deterioration in certain cases but does not convert major deformity into minor ones, and part time bracing can prevent progression of the curve and can even afford some correction.