Background: Brachial plexus blocks provide a wonderful alternative to general anaesthesia for upper limb surgeries. Various adjuvants like opioids, midazolam and 2 agonists have been used to improve the quality of block. Aim: To compare the efficacy of adding midazolam to 0.375% bupivacaine in supraclavicular technique of brachial plexus block for upper limb surgeries. Methods: 100 patients undergoing upper limb surgeries under supraclavicular block were randomized to receive 30ml of 0.375% bupivacaine Group B or 30ml of 0.375% bupivacaine with midazolam 0.05 mg/kg (Preservative free) Group BM. The onset and duration of sensory and motor block, sedation score and number of rescue analgesics needed during 24 hours post-operative period was assessed. Results: The mean time of onset of sensory and motor block was significantly faster in Group BM (11.26±1.5min, 9.56±1.32 min) than Group B (19.08±1.7min, 15.30±2.09 min) respectively. The mean duration of sensory and motor block in group BM (13.81±1.23hrs, 5.25±0.45hrs) were found to be significantly longer than in group B (5.84±0.49 hrs, 5.25±0.45 hrs). Conclusion: The addition of Midazolam as an adjuvant to bupivacaine when compared to plain bupivacaine resulted in rapid onset of sensory block and motor block, prolonged duration of sensory block, reduced number of rescue analgesics in the post-operative period of 24 hours.