BACKGROUND: Tramadol, an opioid n receptor agonist and monoaminergic reuptake inhibitor, has been studied as an adjunct to general and regional anesthesia. Tramadol has been added to local anesthetic regimens for various peripheral nerve blocks, resulting in prolonged anesthesia and analgesia. The purpose of this study was to evaluate the effectiveness of using tramadol as a component of intravenous regional anesthesia (IVRA) to enhance postoperative analgesia. METHODS: Thirty-six patients undergoing hand surgery received IVRA with mepivacaine 0.5%, and were assigned randomly and blindly to one of the following groups: Group I (n = 12) received only 0.5% mepivacaine 40 ml, Group II (n = 12) was given 0.5% mepivacaine 40 ml and 50 mg tramadol, and Group III (n = 12) received 0.5% mepivacaine 40 ml and 100 mg tramadol. After the completion of the operations, analgesic effects were evaluated by using the visual analogue scale (0 - 10). Sedation scores (0 - 3), supplemental analgesic use, and side effects were also evaluated. RESULTS: Patients who received IVRA with 100 mg tramadol reported a significantly lower pain score after tourniquet deflation compared with other groups, and a decreased need for analgesics in the postanesthesia care unit. No significant postoperative sedation, nausea, vomiting, or headache developed in any of the patients. CONCLUSIONS: The addition of 100 mg tramadol to 0.5% mepivacaine for IVRA provided improved analgesia in the postanesthesia care unit after the operation and decreased the need for analgesic supplements after the operation.