Background: Ultrasound assisted Supraclavicular brachial plexus block (BPB) approach has gained popularity because of consistent bony landmarks and less chances of vascular puncture and pneumothorax. The aim is to assess the analgesic efficacy and safety of drug 0.5% Bupivacaine and 0.75% Ropivacaine in BPB patients Methods: These prospective randomized study patients were allocated into two groups of 30 each to receive either 30 ml 0.5% Bupivacaine (group B) or 30 ml 0.75% ropivacaine (group R). Onset, duration, quality of sensory and motor block and side effects were observed in both groups. Results: The mean onset of sensory and motor block is earlier in Group R (6.6 ± 0.7, 8.3 ± 0.6 min) than in Group B (7.5 ± 2, 9.4± 2.2 min). The mean duration of sensory and motor block were significantly longer in Group B (7.3±0.2hrs) and (7 ± 0.2 hrs), respectively, than in Group R (5.3±0.1 hrs) and (5 ± 0.1 hrs), respectively (P < 0.05). The diastolic blood pressure was significantly less in group R at 5,10 and 15 min after giving block.(p<0.03,0.02,0.01). There is no difference in complication rate. Conclusion: Ropivacaine for ultrasound guided supraclavicular BPB has early onset, short duration of sensory and motor blockade and postoperative analgesia without an increase in side effects.