Six cases who were performed completion pneumonectomy after lobectomy or bilobectomy for lung cancer were reported. The reason for completion pneumonectomy was the recurrence of lung cancer, 4 cases; second primary lung cancer, 1 case; and the destroyed lung after bilobectomy, 1 case. The intervals between the first resection and completion pneumonectomy for the patients who were recognized the recurrence were 14, 40, 83, 112 months. This results suggest that it is important that the patients who were performed curative resection are carefully followed. The patients who were performed completion pneumonectomy had the pulmonary function as follows; more than 800 ml as FEV1. The postoperative complication were not observed for the six patients.