From August 1979 to August 1995, 73 consecutive patients with various pulmonary diseases underwent pneumonectomy Underlying diseases were lung cancer(53 cases), pulmonary tuberculosis(10 cases), bronchiectasis(4 cases) and others(6 cases). Operative mortality and complication rate for 73 patients and respiratory capacity for 53 patients at postoperative 6 months were measured, and statistically analysed for the influencing factors. The influencing factors on prognosis included age, sex, pathologic finding (benign or malignant), associated diseases, preoperative pulmonary function test and operation time. The statistically significant factors for operative mortality were preoperative MW(% prep)(P=0.013) and operation time(P=0.009). The factors influencing operative complication was infectious disease (P=0. 015), and for respiratory capacity a postoperative 6 months, preoperative FVC(%. prod) (PED.0018), FEVI(%. prod)(P=0.0024), and MW(%. prod) (P=0.004)) were statistically significant factors. The preoperative FVC(%. tyred), FEVI(% . prod) and MW(%. prod) should be measured exactly. We conclude that preoperative lung function, cardiovascular and nutritional status, postoperative care and infection prevention were important factors to decrease the operative mortality and complication as well as to increase respiratory capacity.