This study was conducted to assess whether ciprofol vs propofol could affect the incidence of postoperative delirium (POD) in elderly patients with lung cancer after thoracoscopic surgery. Patients and Methods: In this study, a total of 84 elderly patients undergoing thoracoscopic surgery for lung cancer were recruited and randomized into two groups to receive anesthesia with either ciprofol or propofol. The primary outcome was the incidence of POD within three days after surgery. Secondary outcomes included the Confusion Assessment Method (CAM) score, intraoperative indicators related to mean arterial pressure (MAP), and cerebral tissue oxygen saturation (SctO 2 ). Moreover, MAP-and SctO 2related indicators associated with POD were analyzed. Results: The incidence of POD was 7.1% and 16.7%, respectively, in the ciprofol group and the propofol group (risk ratio [RR], 0.37; 95% confidence interval [CI], 0.07 to 2.03; risk difference [RD], −9.6%; 95% CI, −23.3% to 4.1%; p = 0.178). Compared with those in the propofol group, patients in the ciprofol group had lower CAM scores three days after surgery (13 (12, 15) vs 15 (14, 17); 12 (11, 13) vs 14 (13, 16); 12 (11, 12) vs 13 (12, 14), p<0.05). Besides, patients in the ciprofol group exhibited higher mean and minimum