Background: Postoperative hemorrhage after lung cancer surgery is a potentially fatal complication. This study aimed to investigate the indications and timing of reoperation for postoperative hemorrhage after lung cancer surgery. Methods: We identified all patients who underwent lung resection and mediastinal lymph node dissection for lung cancer between October 2001 and September 2015 at Sichuan Cancer Hospital, identifying 57 who had undergone reoperation for hemostasis. The records of these 57 patients were reviewed and analyzed. Results: The most common postoperative hemorrhage site was the separation surface of the original pleural adhesions (29.8%). The median time interval between the initial operation and reoperation was 12 hours (range, 2-432 hours), and most patients (77.2%) underwent reoperation within 24 hours. The overall morbidity and mortality rates of reoperation were 50.9% and 5.3%, respectively. The morbidity rates of the early reoperation group (<= 24 hours) and the late reoperation group were 43.2% and 77.0%, respectively, which were significantly different (P=0.033). The mortality rates of the early reoperation group and the late reoperation group were 0 and 23.1%, respectively, which were also significantly different (P=0.010). Conclusions: Once indications of reoperation for postoperative hemorrhage after lung cancer surgery are identified, reoperation within 24 hours after the initial operation can get a better short-term outcome.