Complete resection of Masaoka stage I and II thymoma leads to good prognosis. In recent years, technological development of endoscopy enables thymectomy by thoracoscopic method instead of median sternotomy approach. We perform thoracoscopic thymectomy for thymoma without myasthenia gravis via 2 trocars introduced in unilateral pleural cavity and a small incision on epigastric region with sternal lifting. Thoracoscopic thymectomy for thymoma with myasthenia gravis is performed by bilateral pleural cavity approach with sternal lifting. We had 18 patients with thymoma resected by thoracoscopic thymectomy between 2005 and 2007. Fourteen patients had thymoma with myasthenia gravis. Nine patients had Masaoka I thymoma, 8 had Masaoka II thymoma and 1 had Masaoka III thymoma. The average follow-up period of the patients is 51 months. One patient had a recurrence tumor 56 months after operation. It was developed on the left phrenic nerve from which the resected thymoma had removed. Thoracoscopic thymectomy can be expected as standard surgical treatment for Masaoka I and II thymoma.