470 patients underwent either lobectomy, bilobectomy or decortication at our institution between 1980 and 1991. A residual postoperative pneumothorax was observed in 20.7% of the patients at discharge after removal of the chest tubes. There was no significant correlation between the development of a residual postoperative pneumothorax and the patient's age and gender, the type of operation (lobectomy vs bilobectomy vs decortication) and the date of operation (as related to the introduction of stapling devices). This residual postoperative pneumothorax at discharge resolved without any further treatment in 95% of the patients during follow-up. Complete regression was observed in 91% of the patients within one year after the operation and the duration of regression did not correlate with the size of the pneumothorax at discharge. No empyema was observed in any patient with residual pneumothorax during follow-up, which also holds true for patients who underwent resection or decortication for inflammatory disease. We conclude that there is no need for treatment of residual postoperative pneumothorax, either with space-filling maneuvers at the initial operation or repeat chest tube insertions during follow-up, provided there is no evidence of lung collapse.