Reexpansion of the lung is the most desirable method of filling the pleural space whether it`s contents may be, and closed thoracotomy connected to a water-seal drainage remains the basic therapeutic modality in the treatment of the problems of the pleural space. We usually used rubber mushroom tubes, size No. from 16 to 34 Fr., and performed closed thoracotomy after preliminary thoracentesis to determine the exact depending position. Author reviewed 576 cases of closed thoracotomy which were performed in the Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital, since Jan., 1980 to June, 1984. The results were as follows: 1. The age distribution was 10 days to 76 years old and mean age of the patients was 36.6 year, and the most prevalent age group was twenties, and sex predisposition was male dominant, 86.9%. 2. The most common etiologic disease group was pneumothorax and the most common etiologic disease was traumatic hemothorax. 3. Sites of tubing were predominantly at posterior axillary line, 7th intercostal space and midclavicular line, 2nd intercostal space even though frequent presence of free pleural space. The two sides, right and left difference of occurrence rate was more frequent at right side, 51.2%. 4. Usually the durations of tubing was less than 10 days, 52.6%, and the number of tubes used to the same patient concomitantly was one, 73.9%, and the time of tubing to the same patient was 1st, 83.6%. 5. The common symptom and sign were dyspnea, 50.0%, chest pain, 30.7%, cough, 10.7%, fever, 6.5%. Especially, fever and cough was the most common symptom and sign in pyogenic empyema, 59.3%. 6. The common etiologic lesions of pneumothorax were blebs and bullae, 73.3%, and of pyogenic empyema was pneumonia, 69.0%. 7. The complication rate of closed thoracotomy was 26.0%. Among these complications, infection was 44.7%, and intercostal neuralgia was 25.3%. 8. 70.9% of all patients recovered with only closed thoracotomy and the rest of patient needed additional some necessary managements such as open thoracotomy [Blebectomy, Resection, Pleurodesis, Decortication, Bleeding control], open drainage, thoracoplasty and so on to have successful results.