From Jan 1988 to Dec 1993, 196 consecutive patients with various pulmonary diseases underwent pneumonectomy. Mean age was 54.0 years[range:7-74 . The underlying diseases were lung cancer[154 cases , destroyed lung[29 cases with pulmonary tuberculosis or empyema thoracis and others[13 cases . The overall mortality and complication rate were 5.6% and 14.8%. In the groups of more than and less than 60 years of age, there was significant differences in mortality rate[P=0.004 . In the group of pneumonectomy and pleuropneumonectomy, there was no significant differences in mortality[P=0.164 and complication rate[P=0.052 . In the group of normal and abnormal EKG, there was no significant differences in mortality[P=0.560 and complication rate[P=0.693 . In the preoperative FEV1, preoperative FVC and predicted postoperative FEV1, prognostic cut-off points were 1800cc, 2600cc and 1300cc, and at points, positive predicted value were 12.3%, 10.5%.and 7.7% and negative predicted value were 97.8%, 98.3% and 96.2% respectively. The preoperative FEV1 is the most reliable indicator in assessment of prognosis of pneumonectomy.