The effects of adding 50 ug fentanyl or 3 mg morphine to 0,5% bupivacaine for the epidural anesthesia in cesrean section were evaluated. The 59 women for elective cesarean section were randomly allocated into 3 groups. The first group (n=15) was administered epidurally with 0,5% bupivacaine alone, the second group (n=18), 0.5% bupivacaine mixed with 50 ug fentanyl, and the third group (n=l6), 0.5% bupivacaine mixed with 3 mg morphine. No significant differences among the groups were noted in systolic and diastolic blood pressure, heart rate, respiratiory rate, and tidal volume. There were no significant differences among the groups in the incidence of adverse effects (nausea, vomiting, dizziness, hypotension, pruritus, urinary retention, respiratory depression) in the perianesthetic period and in the onset time of anesthesia up to T4 sensory dermatome. Durations of the anesthesia and postoperative analgesia are prolonged significantly in the second and third groups compared with the first. We found no differences in the neonatal outcome among the groups. Therefore, we conclude that the addition of 50 ug fentanyl or 3 mg morphine to 0.5% bupivacaine during epidural anesthesia for the cesarean section significantly prolongs the duration of anesthesia and postoperative analgesia with no deleterious effects on neonatal or maternal outcome.