Epidural and intrathecal injection of narcotics for postoperative pain relief have been well reported. In an attempt to assess the postoperative analgesic effect of demerol in anal surgery, caudal block was carried out with 1.5% lidocaine mixed with demerol 5 mg(Group II) in 15 patients and demerol 1 0 mg(Group II) in 15 patients. As a control group(Group I), 16 patients were injected with 1.5% lidocaine alone in the epidural space for caudal anesthesia. The incidence of postoperative injection of demerol as needed by the patients for pain control were recorded and compared. As a result of this study, the 3rd group in which 10 mg of demerol were used, appeared to have a significantly prolonged analgesic effect and there were no serious complications observed in our experience such as nausea, vomiting or respiratory depression.