The charts of 62 patients with primary lung cancer who underwent a pneumonectomy at our department from 1979 through 1992 were reviewed for the evaluation of postoperative morbidity and mortality. The 30-day mortality was 3/62 or 4.8%. Postoperative complication occurred in 37 of 62 patients (60%). The most common complication was a supraventricular tachyarrythmia. A major complication, which was defined as one necessitating re-thoracotomy or one which caused death, occurred in 19 patients (3 1%). We analyzed 43 perioperative variables for their predictive value of postoperative morbidity and mortality. Univariate analysis indicated that an elevated serum LDH, low predicted forced vital capacity, low predicted forced expiratory volume in 1 sec (FEV,) were significantly associated with the occurrence of a major complication. A multivariate logistic regression model indicated that a high LDH level, a low predicted FEV, and no extubation following surgery were associated independently with a postoperative major complication. Since only the complete removal of a tumor offers a chance for cure for the treatment of non-small cell lung cancer, it is sometimes necessary to perform a pneumonectomy for these high-risk patients. Patients identified as being at lugh risk of a major complication should be candidates for intensive preoperative evaluation and perioperative care.