Introduction: For routine and emergency upper limb surgeries, brachial plexus block is better alternative to general anaesthesia. As compared to classic Interscalene brachial plexus Block (ISB), Low Interscalene Block (LISB) deposit Local Anesthetic (LA) more caudad causing sensory-motor blockade of upper limb. It acts as bridge between supraclavicular and classic ISB. Local anaesthetic mixture are used to shorten the onset of sensorymotor blockade. Alongside, various adjuvants are mixed with LA to further improve quality of block. Aim: To compare the efficacy of dexmedetomidine and clonidine as adjuvants to LA mixture in LISB for upper limb surgeries to assess onset and duration of Sensory-motor block and to observe any complication associated with block. Materials and Methods: This double-blind, randomised prospective clinical study was conducted on 90 patients, aged 18 to 60 years, posted for upper limb surgeries with American Society of Anesthesiologists (ASA) grade I, II at a tertiary care centre of Government Medical College, Patiala, Punjab, India from February 2021 to November 2021. The patients were randomly divided into three groups. Group I: levo-bupivacaine 0.5% (20 mL)+ lignocaine 2% (10 mL)+ Normal Saline (NS) (1 mL), group II: levo-bupivacaine 0.5% (20 mL)+ lignocaine 2% (10 mL) + dexmedetomidine 50 mcg (1 mL), group III: levo-bupivacaine 0.5% (20 mL)+ lignocaine 2% (10 mL)+ clonidine 50 mcg (1 mL). The parameters observed were: onset and duration of sensory and motor block, any intraoperative complication. Data was compiled with the help of MS-Excel and analysis done with IBM Statistical Package for Social Sciences (SPSS) version 22. Results: The mean onset time of sensory and motor block was faster in group II (4.20±0.62, 5.25±0.89 min) as compared to group III (5.24±0.99, 6.23±0.96 min) and group I (6.48±0.87, 7.03±1.02 min). The mean duration of sensory and motor block was prolonged in group II (743.38±12.55, 673.21±22.29 min) as compared to group III (480.65±14.72, 433.03±7.28 min) and group I (311.28±5.75, 272.03±6.09 min). No adverse effect was observed during this study. Conclusion: Dexmedetomidine was more effective than clonidine as an adjuvant to LA mixture (0.5% levobupivaciane + 2% lignocaine) in low interscalene brachial plexus block and no episode of pneumothorax and phrenic nerve palsy was seen.