Background and Aim: Regional nerve blocks with local anesthetics provide intra operative anesthesia as well as Postoperative analgesia. Our study has been undertaken to compare the onset time, duration and analgesic efficacy of clonidine with dexmedetomidine when added as adjuvant to bupivacaine(0.25%) for brachial plexus block by supraclavicular approach. Methods: 60 patients aged 18-65 years belonging to ASA PS –I & II of both sexes undergoing elective upperlimb surgeries under Brachialplexus block were included in our study. Patients satisfying the inclusion criteria were allotted into 2 groups of 40 each. Group 1: Bupivacaine 0.25%( 35 cc) + clonidine 1 mcg/kg, Group 2: Bupivacaine 0.25%( 35 cc) +dexmedetomidine 1mcg/kg. Results: The mean time for onset of sensory block in group A was (20.23 ±1.104 ) mins and that observed in group B was (14.83±1.744) mins. The mean time for onset of motor block in group A was( 18.43 ±1.135) mins and (12.67±1.539) mins in group B. . Mean duration of sensory block in group A was (476.77±9.313) mins and in group B was (730.13±52.208) mins. The mean duration of motor block in group A was (420.60±8.896 )mins and in group B was( 649.6±45.040 )mins. The mean duration of analgesia in group A was (522.23±11.047) and in group B was (757.13± 44.044) All the above differences were statistically significant with a p value < 0.05%. Conclusion: From our study we conclude that, dexmedetomidine when added to bupivacaine compared to clonidine has 1. Faster onset of sensory block 2. Faster onset of motor block 3. Prolonged duration of sensory block 4. Prolonged duration of motor block 5. Prolonged duration of analgesia 6. Comfortable sedation where the patient can be arousable at any time 7. No significant difference in hemodynamic variables.