BACKGROUND: Patients receiving surgery under local anesthesia might feel anxiety during surgery and suffer pain due to the insufficiency of local anesthesia. The purpose of this study was to evaluate the efficacy and side effects of patient-controlled sedation and analgesia in patients undergoing endoscopic sinus surgery (ESS). METHODS: We studied 63 adult patients. A mixture of 400 mg of propofol and 200microgram of fentanyl (total 44 ml) was infused to the patient at a rate of 10 ml/hr using a PCA device. The lock-out time was 1 minute and the bolus dose was 1 ml. During surgery, we monitored vital signs and sedation state. At the end of surgery, we assessed the degree of satisfaction about pain and anxiety relieving effects by using a questionnaire with a 1 to 10 scale. RESULTS: About 90% of patients were wide awake during surgery, others were drowsy or intermittently sleeping. About 95% of the patients were satisfied with anxiety relief (more than a score of 8) and 84% were satisfied with pain relief in painful episodes (more than a score of 8). Vital signs were within normal limits. The oxygen saturation was maintained above 94% during surgery, except three patients whose oxygen saturation was 92% for short while. Twenty-two percent of the patients complained of pain at their drug infusion sites. CONCLUSIONS: We concluded that patient-controlled sedation and analgesia using the mixture of fentanyl and propofol might be a good way to relieve patient's anxiety and pain without respiratory depression and excessive sedation for those undergoing ESS under local anesthesia.