Regional anesthesia has gained significant popularity in modern anesthetic practice due to its numerous advantages including superior postoperative analgesia, reduced opioid consumption, and minimal systemic side effects. The supraclavicular approach to brachial plexus block is considered the most effective technique for upper limb surgeries, providing dense anesthesia and analgesia. However, the duration of analgesia with local anesthetics alone is often insufficient for prolonged surgeries and postoperative pain management. Various adjuvants have been studied to enhance the quality and duration of regional blocks, with dexmedetomidine emerging as a promising option due to its unique pharmacological properties. This prospective, randomized, double-blind study was conducted to compare the efficacy of two different doses of dexmedetomidine (0.5 μg/kg and 1.0 μg/kg) when added to bupivacaine 0.5% in ultrasound-guided supraclavicular brachial plexus block. A total of 90 patients scheduled for elective upper limb surgeries were randomly allocated into three groups: Group C (control) received 30ml of 0.5% bupivacaine with normal saline, Group D1 received 30ml of 0.5% bupivacaine with 0.5 μg/kg dexmedetomidine, and Group D2 received 30ml of 0.5% bupivacaine with 1.0 μg/kg dexmedetomidine. Primary outcomes included onset and duration of sensory and motor blockade, while secondary outcomes comprised postoperative analgesia duration, total analgesic consumption, patient satisfaction scores, and adverse effects. Results demonstrated that both doses of dexmedetomidine significantly enhanced the quality of brachial plexus block compared to control, with faster onset times, prolonged duration of sensory and motor blockade, and extended postoperative analgesia. The higher dose (1.0 μg/kg) showed superior efficacy in terms of block duration and analgesic effect, though it was associated with increased incidence of sedation and bradycardia. Both dexmedetomidine groups showed significantly reduced postoperative analgesic requirements and higher patient satisfaction scores. The study concludes that dexmedetomidine 1.0 μg/kg provides optimal enhancement of bupivacaine-induced brachial plexus block, making it an excellent adjuvant for upper limb surgeries requiring prolonged anesthesia and analgesia.