Objectives. To highlight the possible complications of medical thoracoscopy (MT) and how to avoid them. Methods. A retrospective and prospective analysis of 127 patients undergoing MT in Nagoya Medical Center (NMC) and Toyota Kosei Hospital. The data about complications was obtained from the patients, notes on the computer system, and radiographs. Results. The median age was 71.0 (range, 33.0-92.0) years and 101 (79.5%) were males. The median time with chest drain after procedure was 7.0 (range, 0.0-47.0) days and cases with talc poudrage were 30 (23.6%). Malignant histology was reported in 69 (54.3%), including primary lung cancer in 35 (27.5), mesothelioma in 18 (14.2), and metastasis in 16 (12.6). 58 (45.7%) revealed benign pleural diseases and TB was diagnosed in 15 (11.8%). 21 (16.5%) patients suffered from complications including lung laceration in 3 (2.4%), fever in 5 (3.9%) (due to hospital acquired infection (HAI) in 2, talc poudrage in 2, and malignancy in 1), HAI in 2 (1.6%), prolonged air-leak in 14 (11.0%), and subcutaneous emphysema in 1 (0.8%). Conclusions. MT is generally a safe procedure. Lung laceration is the most serious complication and should be managed well. HAI is of low risk and can be controlled by medical treatment.