BACKGROUND: Recent evidence suggest that noxious surgical trauma may induce prolonged changes in central neural function that later contribute postoperative pain. So, postoperative pain may be eliminated or reduced if surgical afferent barrages are prevented with local anesthetics or opioid before they reach to the CNS. We studied the preemptive analgesic effect of continuous epidural analgesia under general anesthesia after radical gastrectomy. METHODS: Forty four patients scheduled for radical gastrectomy were investigated. After general anesthesia induction, patients of preemptive group (n=25) were given 40 ml of 0.125% bupivacaine, 0.1 mg/kg of morphine and 75 microgram of clonidine epidurally as a bolus and followed by 10 ml/hour of 0.125% bupivacaine and 0.2 mg/hour of morphine continuously for 10 hours. Patients of non-preemptive group (n=19) were given the same drugs according to the same way after finishing the operations. The effect of preemptive analgesia was assessed by visual analogue pain scale (VAPS) score, and evaluated the time to first analgesic request, and total amount of used analgesics. Side effects were recorded. RESULTS: Postoperative VAPS scores were not different between two groups. Time to first analgesic request were significantly more prolonged and total amount of used analgesics were significantly less in preemptive group than in non-preemptive group. The incidence of side effects except respiratory depression were similar between two groups. CONCLUSIONS: We concluded that despite preemptive analgesic effect was seen in preemptive group, but it was not prominent. Further studies are needed to prove more prominent preemptive effect in major abdominal operation.