Introduction: Nalbuphine a newer synthetic anta opioid with ceiling effect on respiratory depression establishing its efficacy in prolongation and effectiveness in regional block anaesthesia as an adjuvant with local anaesthetic drugs. The aim of this study was to evaluate the effect of nalbuphine in prolongation of duration of post-operative analgesia when it is added as an adjuvant to ropivacaine a local anaesthetic drug in ultrasound guided supraclavicular brachial plexus blocks. Methodology: A prospective randomized double blinded controlled interventional study was carried out to evaluate the effect of nalbuphine10mg as an adjuvant to 0.5% ropivacaine 20ml for post operative analgesia in USG guided supraclavicular BPB in patients undergoing upper limb surgeries. 64 patients of either sex aged 20 to 50yrs and physical status ASA grade 1and 2 were allocated randomly into two groups N and R of 32 each. In group N test group patients were given 20ml of 0.5% Ropivacaine and 10mg of Nalbuphine as an adjuvant while in group R control group patients were given 20ml of 0.5% Ropivacaine and 1ml of normal saline . The outcome and comparison were done in terms of onset and duration of sensory and motor block duration of analgesia and complications if any. Results: Both groups were demographically comparable. The mean onset of sensory block in Group N is 4.78 in 2.24min and in Group R is 5.34 in1.73min that is statistically significant p 0.01857. The mean onset of motor block in Group N is 7.56 in 1.72min and in Group R is 8.72 in 2.72min that is statistically significant p 0.02308. The mean Duration of Sensory Block in Group N was 425.34 in 10.37 min and in Group R was 261.59 in 9.01 min that was statistically highly significant p 0.000001.The mean Duration of Motor Block in Group N was 408.25 in 12.06 min and in Group R was 250.78 in 6.41 min that was statistically highly significant p 0.000001.The mean Duration of Analgesia in Group N was 435 in 12.20 min and in Group R was 274.34 in 55.46 min that was statistically highly significant p 0.000001. no complications were noted in both study groups. Conclusion: Nalbuphine as an adjuvant to Ropivacaine provides comparable results in term of decreasing the duration of onset of sensory and motor block and prolonging the duration of analgesia when compared to ropivacaine alone in USG guided supraclavicular brachial plexus nerve blocks.