Aim:To compare the effect of addition of Clonidine or Dexmedetomidine with 0.5% Bupivacaine under ultrasound guided supraclavicular brachial plexus block in the patients undergoing bony orthopaedic surgeries of the upper limbs. Method and material: The present study was conducted in the Department of Anaesthesiology, Nehru Hospital, B.R.D. Medical college, Gorakhpur, U.P., India after approval by the ethical committee of the institution, a written consent was taken from the patients after explaining to them in detail about the implications of the anaesthetic and the surgical procedure. Our study had 45 patients of ASA Grade I and II patients of either sex, aged 18-60 years, undergoing various bony orthopaedic surgeries on the upper limb under ultrasound guided supraclavicular brachial plexus block. The patients were randomly assigned using "slips in a box technique" to one of the following groups of 15 patients each: Group A(control): Bupivacaine 0.5% (19 ml) +Distil water (1ml) Group B: Bupivacaine 0.5% (19 ml) + Dexmedetomidine 1 μg/kg (1ml) Group C: Bupivacaine 0.5% (19 ml) + Clonidine 1 μg/kg (1 ml) All volumes were made equal by addition of normal saline. Result: There were early onset of sensory and motor block, better quality of block,longer duration of analgesia in group B than group C, without significant difference in heamodynamic parameters and associated complications. Conclusion: Dexmedetomidine with 0.5% Bupivacaine provides better quality of block,early onset and longer duration of sensory and motor block and longer duration of postoperative analgesia as compare to clonidine with 0.5% Bupivacaine in supraclavicular AIbrachial plexus block.