Acute nontuberculous empyema treated conventionally by thoracentesis, thoracostomy drainage, and antibiotics has an unacceptably high rate of morbidity and mortality. Early open thoracotomy to eliminate the empyema with decortication of the fibrinous peel and reexpansion of the lung has proven safe and effective for 25 years. The goals of treatment of acute nontuberculous empyema are: (1) to save life, (2) to eliminate the empyema, (3) to reexpand the trapped lung, (4) to restore mobility of the chest wall and diaphragm, (5) to return respiratory function to normal, (6) to eliminate complications or chronicity, and (7) to reduce the duration of hospital stay. Our studies confirm the normal values to be expected in patients who have had complete recovery from the acute empyema, and we lay to rest any concern that decortication might, in time, limit pulmonary function. We present the cases of 21 children who had acute and mature empyemas that were treated by open thoracotomy and decortication, with an average follow-up of 18 years, among whom there were no deaths or complications.