Background: Evidence has accumulated that opioids can produce potent antinociceptive effects by interacting with opioid receptors in peripheral tissues. Bupivacaine has a potent analgesic effect with early peak onset in the postoperative period. The combination of intrapelvic bupivacaine and morphine has been suggested as an ideal analgesic after endoscopic pelvic surgery. Methods: Sixty patients scheduled for endoscopic pelvic surgery under general anesthesia were allocated randomly to three groups. Group 1 received normal saline 20 ml, group 2 received morphine 5 mg in normal saline 20 ml, and group 3 received morphine 5 mg in 0.25% bupivacaine 20 ml into the pelvic cavity. Postoperative pain was assessed using the visual analogue scale at 1, 2, 4, 8, and 24 hours after the intrapelvic instillation. Supplemental analgesic requirements, vital signs, and side effects were recorded for 24 hours. Results: Intrapelvic morphine and bupivacaine produced significant analgesia after endoscopic pelvic surgery. The patients in group 3 had lower pain scores than those in the group 1 and 2 at 1, 2 and 4th hours. There were no significant differences in the pain scores at 8 hours and 24 hours postoperatively between group 2 and 3. Supplemental analgesic requirements were significantly greater in the groups 1 and 2 than the group 3 for 24 hours. No significant side effects occurred. Conclusion: The intrapelvic instillation of morphine and bupivacaine is effective for the postoperative pain control in patients undergoing endoscopic pelvic surgery.