Introduction: Supraclavicular brachial block is a popular and widely used nerve block technique for perioperative anesthesia and analgesia for upper extremity surgery. The block is performed at level of distal trunks and the origin of divisions, where the brachial plexus is confined to its smallest surface area, thus producing a rapid and reliable block of the plexus. It is the popular technique of anesthesia for upper limb surgeries due to its effectiveness in terms of performance, cost, margin of safety and good post-operative analgesia. It provides rapid onset, dense upper limb anesthesia with a single injection. Materials and Methods: About 90 patients who underwent elective upper limb Orthopaedics surgery during the period of the study were randomly divided into three equal groups of participants each using a computer-based random number generator, i.e., group C, D and F. They were compared for the onset and duration of motor and sensory block and post operative analgesia. Results: Mean onset of sensory and motor block was minimum for fentanyl (7.13 ± 0.94, 9.77 ± 0.82 minutes) followed by dexmedetomidine (7.37 ± 1.06, 11.33 ± 1.61 minutes) and clonidine (8.73 ± 0.98, 12.23 ± 1.57 minutes). Duration of block amongst the three groups showed statistically significant difference, dexmedetomidine (585.13 ± 44.42, 546.07 ± 42.02 minutes) having maximum duration of sensory and motor block followed by clonidine (535.77 ± 32.11, 507.30 ± 33.59 minutes) and minimum for fentanyl (330.03 ± 44.25, 284.67 ± 59.96 minutes). Conclusion: We concluded that adding fentanyl to bupivacaine for supraclavicular brachial plexus block had a faster onset of sensory and motor blockade when compared to dexmedetomidine and clonidine, and dexmedetomidine prolonged the duration of analgesia when compared with clonidine and fentanyl.