An epidural catheter is used in some institutions for postoperative analgesia after liver surgery. However, anesthesiologists may not feel comfortable leaving a catheter in the epidural space because of concern about coagulation disturbances and possible bleeding complications caused by impaired liver function. In this study, we tested a single-shot intrathecal morphine technique and compared it to a continuous epidural naropine infusion for postoperative analgesia in liver surgery. Fifty patients were randomly assigned to an epidural analgesia group (EP group; n = 25) and an intrathecal analgesia group (IN group; n = 25). The quality of analgesia assessed by a visual analog scale (VAS), the side effects, and the additional IV analgesic requirements were recorded. We did not observe any signs of cord compression. Time to first pain drug requirement was longer in the EP group compared to the IN group (25 +/- 18.5 h versus 12 +/- 10.3 h; P < 0.05). In both groups, the VAS remained less than 30 mm throughout the 48-h follow-up period. Consumption of IV morphine with a patient-controlled analgesia device in the IN group was larger (mostly from 24 to 48 h after surgery) than the EP group (12.0 +/- 5.54 mg versus 3.1 +/- 2.6 mg, respectively; P < 0.01). The incidence of vomiting was 4% in both groups, whereas the incidence of pruritus (16% versus 0%) and nausea (16% versus 4%) was more frequent in the IN group. No postdural puncture headache and no spinal hematoma occurred. After liver resection, a single dose of intrathecal morphine followed by patient-controlled morphine analgesia can provide satisfactory postoperative pain relief. The quality of this treatment, according to the VAS, is not inferior to continuous epidural analgesia up to 48 h after surgery.