Epidurally administered morphine is reported to produce analgesia in human. Epidural and intrathecal clonidine is also reported to produce analgesia and to prolong analgesic action of local anesthetics. This study was undertaken to evaluate the analgesic effects of the combination of epidural morphine and clonidine versus epidural morphine alone in patients with postoperative pain. 20 patients were scheduled for postoperative pain relief by epidural block. Patients were received either epidural morphine and clonidine(clonidine group: n=10) or morphine alone(morphine group: n=10) before general anesthesia. To compare clonidine group and morphine group in postoperative analgesia, we used Visual analogue scale(VAS), time and dosage of additional analgesics required and change of forced vital capacity(FVC). 1) There were no statistically significant differences in hemodynamic values during operation between two groups. 2) Although there was no statistically significant difference in postoperative analgesic effect between two groups, clonidine group showed some trend of analgesic effect during postoperative 24 hours. 3) There were no statistically significant differences between two groups in side effects. Epidural clonidine enhances the analgesic effect of epidural morphine clinically without causing more side effects.