AbstractBackground: Addition of adjuvants to local anaesthetic drugs improves onset, duration and quality of brachial plexus block in terms of intraoperative anaesthesia as well as postoperative analgesia very effectively. USG guided block ensures safety ,allowing operators to perform block with greater accuracy under direct visualization. Objective: The study was carried to compare the block characteristics between bupivacaine and lignocaine with adrenaline alone and dexamethasone as an adjuvant to mixture of bupivacaine and lignocaine with adrenaline in ultrasound guided supraclavicular brachial plexus block for orthopedic surgeries at and below elbow. Materials and Methods: After obtaining the approval from the Institutional Ethics committee and written informed consent 60 ASA I and ASA II patients between age 18 to 60 years were divided into two groups. Group N(n=30),received 10ml of Lignocaine 2% with Adrenaline plus 18ml of Bupivacaine 0.5% plus Normal saline 2ml.Group D received 10ml of Lignocaine 2% with Adrenaline plus 18ml of Bupivacaine 0.5% plus Dexamethasone 2ml (8mg).Onset of sensory and motor block, duration of sensory and motor block and duration of analgesia were compared among two groups.Results:Our study revealed that onset of both sensory and motor block was earlier in Group D ,duration of sensory and motor block and duration of analgesia was longer in Group D than Group N. Conclusion: Dexamethasone prolongs the duration of sensory and motor block and duration of analgesia when used as an adjuvant to mixture of Bupivacaine and Lignocaine with Adrenaline as compare to mixture of Bupivacaine and Lignocaine with Adrenaline alonein USG guided supraclavicular brachial plexusblock.