Background: Supraclavicular brachial plexus block is a commonly employed regional nerve block technique for upper extremity surgery. Various adjuvants were added tolocal anesthetics in brachial plexus block to achieve rapid onset and prolonged block. Objective: To compare dexamethasone and dexmedetomidine as an adjuvant to local anesthetic agent in supraclavicular brachial plexus block with respect to onset and duration of sensory and motor block. Methods: Forty ASA I and II patients scheduled for elective upper limb surgeries under supraclavicular brachial plexus block were divided into two equal groups in a double-blinded fashion. Group one was given 0.25% Bupivacaine 2 milligram/kg aslocal anesthetic and Dexmedetomidine 1 microgram/kg as adjuvant. Group two was given 0.25% Bupivacaine 2 milligram/kg and Dexamethasone 100 microgram/kg as adjuvant. Onset and duration of sensory and motor blockade and hemodynamic stability were recorded. All patients were observed for any side effects and complications. All data were recorded, and statistical analysis was done. Results: Sensory block and motor block onset was earlier in dexmedetomidine group. The duration of blockade was also prolonged in dexmedetomidine group when compared with dexamethasone group and is not associated with any major side-effect. Conclusion: Dexmedetomidine is a better adjuvant than dexamethasone in supraclavicular brachial plexus block.