Background:Different adjuvants are used with local anesthetics to improve quality of peripheral nerve blocks. The aim of our study was to evaluate the effect of addition of dexmedetomidine with ropivacaine in supraclavicular brachial plexus block with respect to onset of sensory and motor blockade and duration of blockade and analgesia. Patients and Methods: Sixty patients of ASA grade I and II, aged 18-55 years of either sex scheduled for upper limb plastic surgical procedures under supraclavicular brachial plexus block were randomly divided into two equal groups. Patients in control group R (n = 30) received 29 ml of 0.5% ropivacaine with 1ml normal saline (control) and in study group RD (n = 30) received 29 ml of 0.5% ropivacaine with 1 ml (50?g) dexmedetomidine. The onset and duration of sensory and motor block, duration of analgesia were analyzed in both the groups Results:The mean time of onset of sensory blockade were 5.1?0.91 min and 3.2?0.82 min respectively in group R and RD. Whereas time of onset of motor blockade were 11.21?1.81 min and 6.45?0.92 min respectively in group R and RD. The durations of sensory and motor block were 455.31 ? 19.31 and 365 ? 18.41 min respectively in group R, whereas they were 693 ? 11.01 and 656 ? 18.26 min respectively in group RD. The duration of analgesia was 481.31? 16.01 min in group R compared to 718.32 ? 11.25 min in group RD (p<0.001). Statistically significant difference was found between the two groups with respect to their onset and duration of sensory and motor blockade as well as in their total duration of analgesia. Conclusions: We conclude that in supraclavicular brachial plexus block addition of dexmedetomidine to ropivacaine shortens the onset of sensory and motor blockade and prolongs the total duration of sensory and motor block as well as total duration of analgesia.