BACKGROUND: The analgesic properties of the nonsteroidal antiinflammatory drugs (NSAIDs) have been attributed to their effects on the peripheral synthesis of prostaglandins. Although the preoperative use of NSAIDs has been increasing because of concerns regarding the side effects of opioid analgesics but results of clinical preemptive analgesia studies remain inconclusive. So, we studied the efficacy of preemptive analgesic effects of tenoxicam, new NSAID, on postoperative continuous intravenous analgesia with morphine. METHODS: We studied 40 parturients, undergoing cesarean section, ASA class I or II, randomly divided into two groups. Tenoxicam group were injected tenoxicam 0.3 mg/kg and control group were injected normal saline 3 ml at ten min. before induction. For both groups morphine 0.1 mg/kg was administered as loading dose and 0.015 mg/kg/hr as maintenance dose. We examined verbal quantitative score (VQS) at postoperative 30 min, 1, 6, 12, 24 and 48 hr. Maternal satisfaction, side effects, hepatic and renal function also evaluated after pain control. RESULTS: The values of VQS showed no significant differences between two groups 30 min, 1 and 6hr after start of morphine infusion, but there was significant decrease in tenoxicam group compared to control group 12, 24 and 48 hr after start of morphine infusion (p<0.05). There was no significant difference in maternal satisfaction between two groups and also there were no significant differences in the overall incidences of side effects between two groups. CONCLUSIONS: Preoperative single injection of tenoxicam showed incomplete preemptive analgesic effects on postoperative pain control after cesarean section.