Evaluation of postpneumonectomy space (PPS) by CT in patients with lung cancer for operation-related complication or tumor recurrence is critical, but often difficult. We retrospectively analysed CT scans of 38 patients who underwent pneumonectomy for lung cancer. CT scans were obtained on 7-10th post-operative day for baseline image and at varying intervals of 2 to 24 months thereafter. Usual postoperative findings in patients without complication included mediastinal shifting, changes in subpleural space, changes in parietal pleura, and herniation of contralateral lung. Four patients had postoperative complication including empyema (n=3) and bronchopleural fistula (n=2). Twelve patients showed findings of tumor recurrence such as lymph node metastasis, local recurrence, and pericardial and contralateral pleural effusion. By comparing follow-up CT with baseline CT, we were able to detect early cancer recurrence and postoperative complications. Our results indicate that serial chest CT play an important role in the evaluation of the patients who underwent pneumonectomy for lung cancer.