The few number of severe thoracic scoliosis requiring surgical treatment makes the description of its therapeutic course difficult. Twenty-one cases of severe thoracic scoliosis with Cobb's angle >90 degrees were treated surgically in the past 20 years. Surgical treatment was performed because of an evolutive scoliosis or in case of respiratory or functional impairment. All patients underwent posterior approach after a preoperative preparation by the use of halo-traction. In 6 cases, a previous surgical posterior spinal release was performed before the halo-traction period. Fusion achieved in all cases and the final correction was generally better than preoperative reducibility. The surgical course was guided by the poor functional status of these patients, especially concerning respiratory function. Spinal instrumentation was made up of 3 rods with few spinal implants in the majority of the cases. Surgical correction was made by means of rods narrowing without any rod's rotation procedures. Functional improvement, especially respiratory was noted in all the cases. Nevertheless, postoperative spirometries were not significantly different from the preoperative ones. The aesthetic improvement of the rib hump was disappointing making necessary a complementary thoracoplasty in two cases. Surgical treatment of severe thoracic scoliosis remains justified in adults because of a progressive functional and radiological deterioration with respiratory compromise. We performed spinal fusion by posterior approach only, after a preoperative period of halo-traction. The final correction depends on the preoperative reducibility. We noted a functional and respiratory improvement in all the cases.