We have observed 360 cases of spontaneous pneumothorax from Jan. 1971 to Dec. 1981 at the department of Thoracic and Card iovascular Surgery, Yonsei University College of Medicine. The patients age ranged from 2 days to 95 year-old. The associated pulmonary lesions were shown pulmonary tuberculosis in 158 cases[43.9%], bullae in 35, pulmonary emphysema In 32, pneumothorax in 10, paragonimiasis In 7 and unknown underlying pathology in 109 patients. 70 [51.1 %] out of 1 37 cases who received conservative medical treatment Including thoracentesis were cured completely, but the 67 cases [48.9 %] of remaining uncured patients were treated by surgical procedures. The 290 patients who received surgical management were recovered without recurrent pneumothorax. The surgical procedures were closed thoracotomy drainage or explothoracotomy. The choice of treatment should be based on the extent of pneumothorax or the presence of underlying pulmonary disease. Tube thoracotomywas the most effective procedure in achieving the expansion of collapsed lung. On the other hand, open thoracotomy could be a good approach to recurrent pneumothorax, persistent air leakage, incomplete expansion of the lung and bilateral pneumothorax. The minithoracotomy Is the best procedure to recurrent pneumothorax. [KTCS 1982;3:267-273]