Forty patients, American Society of Anesthesiology (ASA) physical status 1-2, undergoing subtotal gastrectomy were enrolled in this study. The patients were allocated to two groups with or (group P) and without (group C) preoperative epidural fentanyl 100 microg. Postoperatively, all patients received continuous infusion of the study solution, containing fentanyl 30 microg x ml(-1) and 2 mg/ml bupivacaine, at a rate of 0.7 ml x h(-1) for 72 h. The scores on the Prince Henry Hospital self-assessed pain scale (PHPS) were recorded at 0, 4, 12, 24, 48, and 72 h after the surgery. We compared the total rescue doses of analgesics during each period of 24 h until 72 h postoperatively. Although the total rescue doses of analgesics were not different between the groups, the median PHPS score was lower in group P than in group C, except at 0 h after the surgery. Preoperative epidural fentanyl 100 microg may increase the analgesic potency of postoperative epidural low-dose infusion of bupivacaine with fentanyl.