The prupose of prospective randomized multicenter study was to compare intrathecal pethidine with bupivacaine combined with morphine for elective caesarean section. Forty eight full term, G1P0, no history of abdominal surgery, ASA class 1 parturients scheduled for caesarean delivery were included in the study. All parturients received premedication with oral 0.3 M sodium citrate 30 ml. before lumbar puncture. After IV 750 ml/kg acetate solution, parturients were randomly divided into 2 groups. Parturients were given either 5% heavy pethidine 1 mg/kg, upper limit at 50 mg., or 0.5% heavy bupivacaine 2.4 ml combined with morrphine 0.15 mg intrathecally. Results. Caesarean section was successfully performed in all cases. None of the parturients suffered from any major side effects. Apgar score showed 9, 10, 10 in all newborns. The incidences of hypotension, shivering, epigastric discomfort during modified Crede maneuver (the procedure that applied pressure at the fundus or epigastric area for pushing fetal head birth from lower uterine incision) were higher in the bupivacaine combined with morphine group (p<0.05). Drowsiness, low level of sensory blockade (T5-6) and mildly inadequate motor blockade were higher in pethidine group (p<0.05). Other side effects such as pruritus, nausea, vomiting, parturients' satisfaction score and decision to use the same technique for next operation were not different between the two groups. The mean duration of postoperative analgesia was 7.67 ± 2.57and 19.00 ± 3.86 hours in pethidine and bupivacaine combined with morphine groups respectively (p<0.01). Neither early nor late respiratory depression, urinary retention, bronchospasm and postdural puncture headache were detected in this study. We concluded that pethidine can be used as the sole agent for caesarean section and was superior to bupivacaine combined with morphine because of antishivering effect, less hypotension, low epigastric discomfort during modified Crede maneuver as well as cheaper and more sedative effect. However, pethidine has short sensory action (mean 52.92 ± 6.41 min). and less postoperative analgesia than that of bupivacaine combined with morphinel.