Context: Dexmedetomidine as an adjuvant to local anesthetics in peripheral nerve blocks has been used in only a few studies. Aims: We aimed at assessing the effect of dexmedetomidine as an adjuvant to ropivacaine in supraclavicular brachial plexus block. Settings and Design: Random, controlled, and triple blind. Materials and Methods: Sixty American Society of Anesthesiologist grade I and II patients of either sex scheduled for elective upper limb surgery under supraclavicular brachial plexus block were divided into three equal groups in a prospective randomized double-blind controlled manner. For block patients in Group C received 0.5% ropivacaine (30cc), 0.5% ropivacaine with 50 μg dexmedetomidine (30cc) in Group D and 0.5% ropivacaine (30cc) in Group D-IV along with intravenous infusion of 50 μg dexmedetomidine in normal saline. Statistical Analysis Used: IBM-SPSS software version 17, Chi-square test, Mann-Whitney U-test. Results: Demographic profile and surgical characteristics were similar in all the three groups. Sensory block and motor block onset was earlier in group D than in group D-IV and group C. The sensory block and motor block duration was also prolonged in group D when compared with group D-IV and group C. The duration of analgesia was significantly longer in group D and D-IV when compared to group C. Conclusions: Dexmedetomidine as an adjuvant to 0.5%ropivacaine in ultrasound guided brachial plexus block shortens the sensory as well as motor block onset time, prolongs sensory and motor block duration and also increases the duration of analgesia. The action of dexmedetomidine most probably is local rather than centrally mediated.