Abstract Purpose: To evaluate the effect of adding dexamethasone 5mg or dexmedetomedine 1ug/kg on levobupivacaine action during ultrasound guided supraclavicular brachial plexus block technique. Materials and Methods: In this prospective randomaized double blind clinical study, 120 patients were equally divided into four groups according to the injectate LA into : Group B: 30 ml of bupivacaine 0.25%. Group L : 30 ml of levobupivacaine 0.25%. Group L +D : 30 ml of levobupivacaine 0.25 % + 5mg of dexamethasone. Group L + DEX: 30 ml of levobupivacaine 0.25 % + 1 ug/kg of dexmedetomedine . All patients had recievied single shot ultrasound guided supraclavicular brachial plexus block with using nerve stimulation. Parameters recorded in the study include the following: Onset and duration of both sensory and motor block and duration of analgesia. Haemodynamic changes (blood pressure and heart rate) and a verbal numerical pain rating scale (V.N.P.R.S.) during the first 24 hours. Serum cortisol level at 1 and 4 hour post injection. Total analgesic requirements calculated.. Any evidence of complication. The patients satisfaction with the anesthetic technique was assessed. Data were analyzed with the paired sample t-test, analysis of