BACKGROUND: Local anesthetics combined with an opioid are frequently used as a postoperative epidural analgesia, to minimize individual doses and to reduce unwanted side effects. The aims of this study were to compare analgesic effectiveness, occurrence of motor block and other side effects of a 48 hr postoperative continuous epidural infusion of 0.1% bupivacaine/morphine or 0.1% ropivacaine/ morphine. METHODS: Forty female patients scheduled for an elective total abdominal hysterectomy under general anesthesia were randomized in a double-blind fashion to receive either 0.1% bupivacaine with 0.02 mg/ml morphine or 0.1% ropivacaine with 0.02 mg/ml morphine using a continuous epidural analgesia pump at a rate of 4 ml/hr during the postoperative 48 hours. After the operation, we assessed the blood pressure, heart rate, visual analog scale (VAS), side effects, additional analgesic requirement and time to ambulation for 48 hours in 12-hour intervals. RESULTS: There were no significant differences in VAS on rest and cough between the groups, but VAS on deep breathing and position change were significantly lower in the bupivacaine group compared to the ropivacaine group. Side effects were similar in both groups except paresthesia. Time to ambulation was earlier in the ropivacaine group compared to the bupivacaine group. CONCLUSIONS: Both the postoperative continuous epidural infusion of 0.1% bupivacaine with morphine and 0.1% ropivacaine with morphine provided similar pain relief and side effects. However, earlier recovery of ambulation in patients receiving ropivacaine/morphine will improve outcome after abdominal surgery.