Background: The aim of this study is to identify the effectiveness of perioperative pneumoperitoneum to prevent air leak after the lobectomy-bilobectomy operations for lung cancer. Methods: A prospective study was designed on consecutive 50 patients who had lobectomy-bilobectomy operations for lung cancer and whose remnant lung had failed to fill the half of the hemithoracic cavity under 30 cm H2O positive pressure ventilation during the operation with totally relaxed diaphragm. The patients were divided into two groups: group 1 (25 patients) with perioperative pneumoperitoneum, group 2 (25 patients) without perioperative pneumoperitoneum. Results: The statistical analysis between the two groups did not show any significant difference in terms of age, preoperative FEV1, and the type of resection. Perioperative pneumoperitoneum significantly reduced the duration of postoperative air leak (2.2+/-1.15 days vs. 6.04+/-3.27 days p<0.0001) and total chest tube drainage time (3.84+/-0.98 days vs. 7.88+/-3.16 days p<0.001). Conclusion: Perioperative pneumoperitoneum after lobectomy-bilobectomy operations for lung cancer is an effective method to decrease air leak and chest tube drainage time.