Background: Interest in supraclavicular brachial plexus blocks has been rekindled using sonographic guidance to locate the brachial plexus. Various adjuncts have been suggested to potentiate the anesthetic and analgesic effects of local anesthetic agents. We designed this randomized double-blind controlled study to compare the effects of dexamethasone and fentanyl when added to a mixture of bupivacaine and lignocaine in supraclavicular blocks in patients undergoing forearm surgeries. Methods: Sixty-six patients aged between 20 to 60 years old belonging to ASA one or two were recruited prospectively, double-blinded, and randomized way. Supraclavicular block under sonographic guidance was performed in the three groups by using injection bupivacaine (0.5%) 20 cc + injection lignocaine (2%) 10 cc + injection 0.9% normal saline; 2ml (Group S), injection bupivacaine (0.5%) 20 cc + injection lignocaine (2%) 10 cc + injection dexamethasone 8 mg (Group D), and injection bupivacaine (0.5%) 20 cc + injection lignocaine (2%) 10 cc + injection fentanyl 50 µgm (Group F). The onset time of sensory and motor block, duration of sensory and motor block, and hemodynamic variables were recorded. Results: Group D showed a significantly greater sensory and motor block duration than other groups ( P = .001). Comparison of hemodynamic variables failed to reveal any statistically significant differences between all groups. Conclusion: Both dexamethasone and fentanyl are good adjuvants in the supraclavicular block, but dexamethasone is better, given faster onset and duration of analgesia.