Abstract: Objective To evaluate the efficacy and safety of intravenous anesthesia with remifentanil and propofol for colonoscopy in the elderly. Methods Thirty old patients scheduled for colonoscopy were randomly allocated into remifentanil group and fentanyl group. Those in group remifentanil received remifentanil at the dose of 0.05 μg/kg·min with micropump, while those in group F were given a bolus injection of fentanyl at 1 μg/kg intravenously. One minute later, all the patients were given a loading dose of propofol of 0.4 mg/kg followed by boluses of propofol (0.2 mg/kg) administered intermittently until Ramsay sedation scale Ⅲ-Ⅳ. The induction time of anesthesia, intubation time of colonoscope, time of recovery from anesthesia and stay in the postanesthesia care unit (PACU) were recorded. The mean arterial pressure (MAP), heart rate (HR), pulse oxygen saturation (SpO₂) and respiratory rate (RR) were measured and recorded with noninvasive monitoring. The lower limb movement, apnea, dizziness, body weakness, nausea and vomiting, and chest wall rigidity were recorded during operation. All the patients were reviewed for satisfaction after the operation. Results The time of anesthesia induction, intubation time of colonoscope, time of recovery from anesthesia and stay in PACU in remifentanil group were shorter than those in fentanyl group (P<0.05), and propofol consumption was significantly less in the former group (P<0.05). Greater MAP decrement was observed in remifentanil group (P<0.05). Fewer patients had lower limb movement while more had respiratory depression in remifentanil group than in fentanyl group. The rate of patient-rated satisfaction was significantly higher in remifentanil group (P<0.05). Conclusion Intravenous anesthesia with remifentanil and propofol for colonoscopy is safe and reliable, which can be a good alternative for anesthesia in outpatient operation for the elderly.