Background: Extended thymectomy is indicated for patients with myasthenia gravis (MG) when drugresistance or dependence is seen. We have employed a technique for subcostal thoracoscopic extended thymectomy (STET) on patients with MG. Conclusions: This procedure showed satisfactory results for patients with MG. Moreover, the STET approach is more easily for surgeons to fully reveal the bilateral phrenic nerve and the upper thymic poles. We believe that STET is a satisfactory procedure for performing extended thymectomy in well selected patients.