The clinical effects of epidural nalbuphine were compared to those of epidural morphine in sixty Cesarean delivery. They were physical status 1 or 2 by ASA classification and randomly divided into three groups. They were administered nalbuphine 5 mg(Group N5), nalbuphine 10 mg(Group N10) or morphine 3 mg(Group M3) through an indwelling epidural catheter at the time of peritoneal closure. During the first postoperative 24 hours, their analgesic effects were evaluated by visual analogue scale(0-10), respiration rates and Trieger dot test. The severity of side effects(0-2) was also evaluated. The results were as follows ; 1) The number of patients who needed additional epidural analgesics was least in group M3 (p<0.05). There was no significant difference between group N5 and group N10. 2) The duration between the first and second epidural administration was ; 19.2 hours in group M3, 8.6 hours in group N10 and 5.4 hours in group N5. There was a significant difference each group (p<0.05). 3) From the fourth post operative hour, both groups receiving nalbuphine showed a higher VAS score compared to group M3(p<0.05). 4) The incidence of pruritus, nausea, vomiting and voiding difficulty were more severe in group M3 compared with the other groups. However the severity did not increase with increasing nalbuphine dosage. 5) There were no patients showing objective sedation or low respiration rate(10 times/minute). We concluded that epidural administration of nalbuphine 5 mg or 10 mg is one way of post operative pain control. Its side effects were less than epidural morphine, but it is a less convenient in the method of analgesia.