Objective To summarize experiences of surgical treatment and long-term results of myasthenia gravis (MG). Methods Two hundred thirty-six patients underwent thymectomy for MG in our department from Jan.1978 to Dec. 2002. The perioperative management, relative factors of postoperative crisis and long-term results were analysed. Results In 236 patients postoperative crisis took place in 44 cases accounted for 18.6%. The occurrence of postoperative crisis was related to preoperative management, modified Osserman clinical classification and combination with thymoma. Three cases died in the postoperative periods. Among them, one died of acute respiratory distress syndrome induced by aspiration and the other died of crisis. The effective rate in 1, 3, 5 years was 84.6%, 91.0% and 89.0% respectively. Conclusions Thymectomy for MG is safe and effective. Delayed extubation could decrease the needs of tracheotomy in patients with high risk factors for postoperative crisis. The partial sternotomy approach is less traumatic but the long-term effects of surgery are identical to those reported by the most authors.