Eighty-seven adolescents with idiopathic scoliosis (77 female and 10 male patients) who underwent posterior spinal fusion with instrumentation using only allograft bone for graft material were evaluated retrospectively. The average age at surgery was 14 years 3 months. Each patient had a minimum 2-year followup, with an average of 3 years 5 months followup. The average preoperative curve was 59 degrees thoracic (range, 31 degrees-90 degrees) and 52 degrees lumbar (range, 21 degrees-65 degrees). At followup, the thoracic curve measured an average of 35 degrees and the lumbar curve measured an average of 34 degrees. The average loss of correction from the immediate postoperative period until last followup was 6.5 degrees or 11% in the thoracic curve and 10 degrees or 19% in the lumbar curve. There were seven reoperations; one of these reoperations involved repair of a pseudarthrosis. There was one clinical infection. The typical patient had a 2-ounce allograft at an average cost of $800. The patients' average loss of correction, complication rate, and reoperation rate compare favorably with results reported in other series using autograft bone. The authors of this study showed the ability of allograft bone to produce reliable results with a satisfactory outcome. The potential advantages of using allograft must be weighed against the potential disadvantages before recommending its routine use.