Open-window thoracostomy (OWT) was performed in 21 cases of empyema. The indications were postpneumonectomy empyema with (n = 6) or without (n = 1) fistula, early recurrent empyema after decortication (n = 6), chronical empyema in ill elderly patients with (n = 5) or without fistula (n = 2), and total unilateral lung gangrene with a large fistula of the main bronchus after radiotherapy and chemotherapy (n = 1). All cases presented with severe sepsis, eight of them with acute septic shock, and six with signs of multiorgan failure. Three to five ribs were resected, the muscles and skin were sutured to the ribs confining the window located at the lowest point of the empyema cavity, while the intercostal muscles of the resected ribs were used to close fistulae. The cavity was packed with dressings every day. In all cases, the sepsis subsided immediately after OWT. With the exception of one patient with postpneumonectomy empyema, who died of contralateral pneumonia on day 36, no surgery-related complications were seen. Four further patients died of unrelated causes 2, 4, 5, and 7 months, respectively, after OWT. In one of them, the OWT had been closed. Up to this time, obliteration and closure of the cavity has been carried out in 7 cases by using thoracoplasty (n = 2) or predicted muscle flaps (n = 5) either in the early course or after a delay of 11 to 23 months, with fair functional and cosmetic results. In one further case, operative closure has been planned. In seven of the eight remaining patients, four of whom declined further operations, the cavities closed spontaneously, despite their initial size after intervals of between 11 and 21 months.