In a double-blind placebo-controlled trial we compared perioperative pain relief using different intrathecal opioid regimens given with bupivacaine during spinal anaesthesia for elective caesarean section. One hundred and sixteen patients undergoing elective caesarean section were divided into four groups (A, B, C, D) of 29 patients each. In addition to hyperbaric bupivacaine (12-14 mg), group A received 1 ml of normal saline, group B 25 microg of fentanyl, group C 100 microg of morphine, and group D received both fentanyl 25 microg and morphine 100 microg intrathecally. The quality of intraoperative analgesia was similar in all the groups receiving opioid. The use of the opioids in association, however, was found to increase the incidence of side-effects. The quality of postoperative analgesia with fentanyl, when used alone, was found to be inferior to that with morphine. The combination of opioids offered no advantage over morphine alone.