To assess the clinical manifestations and therapy of secondary spontaneous pneumothorax (SSP), 123 episodes of SSP in 67 patients were retrospectively reviewed and were compared with 254 episodes of primary spontaneous pneumothorax in 130 patients. The major underlying lung diseases associated with SSP were emphysema (22 patients) and tuberculosis (21 patients). The average age of patients with SSP was 66.8 years, and the most common symptom was dyspnea. The average arterial oxygen tension at onset of SSP was 61.1 +/- 12.1 mm Hg (mean +/- standard deviation), which was lower than that of patients with primary spontaneous pneumothorax (p < 0.01). The recurrence rate of open thoracotomy with pleural abrasion was 12.5% (3 of 24 episodes), which was not lower than that of thoracostomy tube drainage with chemical pleurodesis using tetracycline (recurrence rate, 18.8%) (p > 0.5). We concluded that considering the high age of the patients, the presence of underlying lung diseases, and the increased operative risk, thoracostomy tube drainage rather than open thoracotomy was preferred as the first choice of therapy for SSP.