Post pneumonectomy empyema either with bronchopleural fistula or without bronchopleural fistula is an infrequent postoperative complication, but very serious and critical problem. But it is of some interest that the development of a postoperative empyema following resection for carcinoma of the lung might have a favorable effect on the survival of patients in recent speculation of the literature. We have experienced 4 cases of postoperative empyema following pneumonectomy for carcinoma of the lung at department of chest surgery, Yon Sei University, medical college during 11 years from Jan. 1968 to June 1980. Histologically, 3 cases were demonstrated squamous cell carcinoma except one oat cell carcinoma. Onset of postoperative empyema occurred over a wide range of time, from as early as the 5th postoperative day to insidious onset 6 months after pneumonectomy. The most common organisms isolated from the empyema cavities were staphylococcus aureus, pseudomonas aeruginosa and gram negative bacilli. All cases had a large number of organisms and more infections but not single infection. 2 out of 4 cases are treated with open pleural window drainage and irrigation with antibiotic`s solution 2 or 3 times per week by this time and postoperative general course is not eventful. One is alive to 2 years 3 months, another is alive to 8 years 11 months until now. And 2 out of 4 patients is survived over 4 years 10 months. Analysis of postoperative empyema complicating pneumonectomy for bronchogenic carcinoma revealed an increase in 4 year 10 months survival [50%].