Background. The treatment of patients with myasthenia gravis (MG) may include thymectomy. The objective of this study was to analyze the outcome of video-assisted thoracoscopic surgical (VATS) extended thymectomy and to compare characteristics of patients with MG with and without thymoma. Methods. Between 2002 and 2009, 247 patients with MG underwent VATS thymectomy in our department and were subdivided into 2 groups: MG without thymoma (n = 176) and MG with thymoma (n = 71). Complete stable remission (CSR) was the primary endpoint for efficacy. Results. There were no intraoperative deaths and 4 cases required conversion to median sternotomy. There was a significant difference between the 2 groups regarding preoperative and postoperative myasthenic crisis. Two hundred nineteen patients were followed for 4 months to 9 years: 152 had thymoma and 67 did not have thymoma. The cumulative probabilities of reaching CSR were 37.5% in patients with MG without thymoma and 28.3% in patients with thymoma, respectively. Forty months after surgery there was no significant difference in CSR between the 2 groups. Two years after surgery, 30 patients without thymoma achieved CSR and disease was exacerbated in 2 patients after CSR had been achieved. Ten patients with thymoma achieved CSR, and exacerbation occurred in 5 patients with thymoma. Two patients without thymoma died of myasthenic crisis, whereas 3 of 4 patients with thymoma died of myasthenic crisis, and 1 death was attributable to recurrent disease. Conclusions. Video-assisted thoracoscopic surgery thymectomy can produce a satisfactory long-term result. MG with thymoma seems more severe and its prognosis after thymectomy is not as optimistic as that of MG without thymoma. Special perioperative attention should be paid to patients with MG and thymoma to decrease the possibility of postoperative myasthenic crisis and reduce postoperative death. (Ann Thorac Surg 2012;93:240-4) (C) 2012 by The Society of Thoracic Surgeons