Background: Preoperative analgesia may prevent nociceptive inputs generated during surgery from sensitizing central neurons and therefore may preempt postoperative pain. Although preemptive analgesia has shown to decrease postinjury pain in animals, studies in human are not consistent. We studied whether epidural morphine injection before surgical incision could affect postoperative pain and analgesic demands, compared with injection after removal of specimen. Methods: Forty patients scheduled for radical subtotal gastrectomy were randomly assigned to one of two groups for prospective study in a double-blind manner. Group 1 received an epidural injection of 3 mg of morphine in 8 ml of 0.9% saline before surgical incision, and Group 2 after removal of specimen. Postoperative pain relief was provided with I.V. patient controlled analgesia (PCA) system. Numerical rating scales for pain and mood, Prince Henry Hospital scores for pain, cumulative PCA analgesic consumptions, and incidence of side effects were assessed at 2, 6, 12, 24, 48 hours after operation. Results: Cumulative PCA analgesic consumption in group 1 was significantly less than in group 2 at 2, 6 hours after surgery. Pain scores and the incidence of side effects were similar in both groups. Conclusions: Preoperative analgesia with epidural morphine showed little difference in patient controlled analgesic consumption after upper abdominal surgery compaired to intraoperative morphine.