Twenty-six adults, ranging in age from nineteen to fifty-eight years old, were treated for idiopathic scoliosis by two-stage anterior and posterior spinal fusion. The goals of the combined procedure were to increase correction of the curve and decrease the rate of pseudarthrosis. Preoperatively, the major curves measured an average of 83 degrees, and on the best side-bend they averaged 59 degrees, a 29 per cent degree of flexibility. At the time of discharge from the hospital the curves had improved to an average of 44 degrees, a correction of the preoperative curve of 39 degrees or 47 per cent. At an average length of follow-up of forty-nine months, the major curves measured an average of 50 degrees, a 41 per cent correction compared with the initial curves. Twenty-three of the major curves were better than when they were measured on the preoperative radiograph of the best side-bend, by an average of 15 degrees, but eight curves were either the same or worse. No patient had pseudarthrosis or permanent neurological injury. It is our conclusion that a two-stage anterior and posterior fusion is of value for the treatment of the adult who has a rigid curve that requires maximum correction to allow the head, shoulders, and torso to be centered over the pelvis. We do not recommend the use of instrumentation for the anterior fusion as this did not increase the correction of the curve in this series of patients.