A group of 235 patients were treated between 1981 and 1993 for primary spontaneous pneumothorax. Immediate recovery was obtained in 150 (75%) out of 8 in whom drainage had been applied, and in a total of 79 who had been operated. Fifty of the remaining 52 patients with the first episode of pneumothorax, had repeated paracentesis with no complete lung expansion prior to operation, and 2 were referred to pleural cavity drainage. Three out of 79 operated patients, required re-thoracotomy (2 on the second day, and 1 on the eighth day following operation) because of hemothorax. In 3 patients an infection developed, thereupon a prolonged drainage of pleural cavity was used with good result.