Background and Aims: Different additives have been used to prolong Brachial plexus block. We evaluated the effect of adding Dexmedetomidine to Ropivacaine for Ultrasound guided Supraclavicular Brachial plexus blockade. The primary endpoints were the onset and duration of sensory and motor block and duration of analgesia. Materials and Methods: A total of 60 patients (18-60 years) satisfying inclusion and exclusion criteria posted for elective upper limb surgeries under supraclavicular Brachial plexus block were divided into two equal groups (Group R and RD) in a randomized, double-blind fashion. In group RD(n= 30) 30 ml 0.5% Ropivacaine plus 2 ml (50 micrograms diluted to 2ml ) of Dexmedetomidine and group R (n = 30) 30 ml 0.5%  Ropivacaine plus 2 ml normal saline were administered in Ultrasound guided supraclavicular block. Sensory and motor block onset times and block durations, duration of analgesia, and side effects if any were recorded for each patient. Results: Demographic parameters were comparable in both groups. Onset time of sensory and motor block were shorter in Group RD (6.1±3.4 min and 8.9±3.08 min respectively)than in Group R (8.3±4.4 min and 13.0 ± 5.6 min respectively) (p = 0.001). Duration of sensory and motor blockade were longer in Group RD (630.50±208.2 min and 545.9±224.0 min respectively) than in Group R (400.8± 86.6 min and 346.9±76.9 min) (p = 0.001). Duration of analgesia was longer in Group RD (805.7±205.9 min) than in Group R (411.0±91.2 min) (p = 0.001). Intra-operative hemodynamics were significantly lower in group RD (P < 0.05) without any adverse sideeffects. Conclusions: Dexmedetomidine when added to Ropivacaine for Brachial plexus block shortens the onset time and prolongs the duration of the block and the duration of post-operative analgesia.