After the advent of the effective antimicrobial drugs, empyema of the pleural cavity came to be considered an infrequent disease. However, in recent years the problem of empyema is increasing, probably due to bacterial changes associated with the use and misuse of antimicrobials as well as alterations in the host associated with increased longevity and chronic disease. During the 10 years period from 1957, Sop. to 1977, Aug., we experienced 152 cases of empyema, of which 37 were scheduled on open thoracotomy drainge for chronic empyema. 1. The ratio of male to female was 3.6:1 with male predominance and 64% of total was above 40 years old in age distribution. 2. The cardinal symptoms were fever[70%], dyspnea[40.5%], and sputum[40.5%]. The leucocytosis were observed in 75.7% of all cases. The hemoglobin level showed subnormal in 21.6% of all cases. 3- The underlying pathology predisposing to empyema were postoperative empyema [35.1%] and tuberculosis[32.4%] in order. 4. The pathologic organisms by bacterial culture in 37 patients were Pseudomonas [24.3%], Staphylococccus [21.6%], Streptococcus [21.6%]., no growth [8. 1%] and the remainders. 5. The late results were as follow; a. Spontaneous closure was seen in 10 patients and all of them belongs to non-tuberculous group. Their mean duration was 14 months. b. Still opened are eight; 6 in tuberculous group, remainders in non-tuberculous group. c. Secondary closure was performed in 6 patients, of which 5 cases showed successful secondary closure but one failed. The mean duration from OTD to secondary closure was 46.3 days. d. Eleven patients were not followed. e. Two patients were expired; one was due to progressive cachexia and pulmonary insufficiency, the other due to gastrointestinal bleeding unrelated to empyema.[KTCS 1978;1:35-41] abstract[-][42-45]