Background : Brachial plexus blocks is useful alternative to general anesthesia for upper limb surgeries. They provide better intra-operative hemodynamic stability and also better postoperative pain relief. levobupivacaine is long acting local anesthetic which is an Senantiomer of the bupivacaine with less cardiovascular and central nervous system toxic effects. Adding adjuvant to local anesthetic for peripheral nerve blocks may enhance the duration anesthesia and the analgesia. Materials and methods : 60 of ASA I and II patients were randomized into two groups Group DM received 0.25% levo-bupivacaine(30ml) + dexmedetomidine 50 mcg (0.5 ml) + normal saline(1.5ml) Group DX received 0.25% levo-bupivacaine(30ml) + dexamethasone 8 mg(2 ml).Parameters noted are onset and duration of sensory and motor block, hemodynamic changes, time for rescue analgesia. Results : Onset of sensory and motor block is early in group DM compared to group DX. Postoperative analgesia was markedly prolonged in DM group than in DX group (p=0.0118). Conclusion : Dexmedetomidine is superior to dexamethasone in providing effective block characteristics in the interscalene block.