• In simple spontaneous pneumothorax, as distinguished from tension pneumothorax and hemopneumothorax, a variety of therapeutic approaches may be considered. Three different approaches were used in 42 nontuberculous patients with simple spontaneous pneumothorax. No underlying pulmonary disease was found in 32; in the remaining 10 the etiology ranged from asthma to sarcoma. In 15 of the cases, with partial collapse of the affected lung, rest was sufficient treatment, and the average time required for complete reexpansion of the lung was 12 days. Closed thoracotomy, consisting of the insertion of a catheter in the second intercostal space anteriorly and the maintenance of suction for two days, was done in 12 of the more severe cases; in those cases in which it was successful the average time required for reexpansion of the lung was 3 1/2 days. It was much quicker and more effective than repeated aspiration.