The etiology, microbiologic findings, and management of 82 episodes of empyema treated by our unit over a period of 6 years were analyzed. Average patient age was 54 years. Eighty-two percent had underlying disease such as alcoholism (29 percent), malignancy (23 percent), and diabetes mellitus (20 percent). Sixty (73 percent) had an empyema develop secondary to a bronchopulmonary infection. Other etiologies were as follows: infradiaphragmatic sepsis, five cases; iatrogenic, ten cases; and idiopathic, seven cases. Cultures were positive in 76 cases and negative in the remaining 6 (2 positive Gram stains, 1 positive under bacilloscopy, and 3 were sterile). Anaerobes were isolated from 25 and aerobes from 47 of the positive cultures. A single bacteria was isolated from 43 and multiple organisms (average: 2.63/case) grew on the remaining 33 positive cultures. Length of hospitalization averaged 37 days. Seven patients received antibiotics only, thoracentesis was performed on three, intercostal chest tube drainage was required in 72, and more aggressive surgery was performed on 12 patients (7 with fibrothorax and 5 with pneumonectomy). Streptokinase was instilled into the pleural space of eight patients with good results. Pleural drainage superinfection occurred at a rate of 8.5 percent. Nine patients died; the remaining recovered. Only three deaths came about as a direct result of the empyema.