This study describes minimally invasive surgery using video-assisted thoracic surgery (VATS) for thymic diseases. Our procedure has been changed in the last decade from sternum-lifting thoracoscopic surgery with mini-thoracotomy to complete thoracoscopic surgery. Indications for this method include benign thymic disease, non-invasive thymoma or myasthenia gravis (MG). We performed these procedures for 27 cases, including 12 cases of thymic cyst, 10 cases of thymoma without MG, 3 cases of thymoma with MG and 2 cases of MG alone. In all cases of thymoma, tumor size was less than 5 cm. Complete VATS, VATS with mini-thoracotomy and sternum-lifting VATS were performed in 20, 4 and 3 patients, respectively. Complications were phrenic nerve palsy in 2 cases and postoperative bleeding in 1 case. We always use ultrasonic devices in this procedure. No recurrences have been identified in any cases. Even though definitive evidence is lacking for use of a unilateral approach with VATS for thymoma and MG, VATS thymectomy appears acceptable as a less-invasive procedure with less pain and rapid recovery.