An otherwise healthy boy was referred to the University of Iowa Hospitals and Clinics at the age of fourteen years and eight months for the evaluation of idiopathic scoliosis. There was no family history of scoliosis or neuromuscular disorders. Radiographs of the spine demonstrated an upper left thoracic curve of 34 degrees, a lower right thoracic curve of 43 degrees, and a lumbar curve of 18 degrees. The Risser sign was 0. An operation was recommended because of the high probability of progression of the curves. By the time that the operation was performed, at the age of fifteen years and three months, the lower thoracic curve had progressed from 43 to 52 degrees. A posterior spinal arthrodesis was performed with use of autologous bone from the iliac crest and Cotrel-Dubousset instrumentation from the second thoracic to the first lumbar vertebra. The operation and the postoperative course were uncomplicated. At the time of the two-year follow-up examination, the patient was asymptomatic and was functioning at a normal level. Radiographs made at that time revealed good coronal and sagittal alignment of the spine. A solid fusion was present with no loss of correction, and the hardware was intact.