Background: When adjuvant is used along with local anaesthetic agents they augment the onset of action, prolong the duration of analgesia and improve quality of block. Nowadays different drugs have been used as an adjuvant with local anesthetics in brachial plexus block to achieve quick, dense and prolonged block. Objective: To evaluate the effects of adding  a2 receptor agonist Dexmedetomidine and Clonidine to local anaesthetics in brachial plexus block through Supraclavicluar route in upper limb surgeries. Materials and Methods: The present study was conducted on 100 patients of 18 to 60 years age group of either sex of ASA physical status I or II planned for upper limb surgery. According to the adjuvant along with anaesthetic agent given to the patients; they were randomly divided into two groups of 50 patients each. Group A received Dexmedetomidine while in Group B; Clonidine was used as an adjuvant to local anesthetics. Supraclavicluar brachial plexus block was performed according to the group selected. All patients were observed for onset and duration of sensory and motor block, duration of analgesia, VAS score. Results: In Group A Mean age of patients was 35.64 years while in group B,it was 37.48 years. The average duration of surgery was 139.6 minutes in Group A while 147.2 minutes in Group B. Dexmedetomidine (3.5 mins, 6.48 mins) and Clonidine (4.2 mins, 6.48 mins) has similar onset of sensory and motor block time respectively. Both have longer motor block duration than sensory block duration. Dexmedetomidine has significantly prolonged sensory and motor block duration than clonidine (p<0.0001). Dexmedetomidine also has longer duration of analgesia in compared to clonidine withp<0.0001. Conclusion Dexmedetomidine has better profile in terms of duration of sensory and motor block and duration of analgesia, as an adjuvant to supraclavicular brachial plexus block in comparison of clonidine.