Background: Several adjuvants have been suggested to enhance the analgesic effect of local anesthetics. This study aimed at comparing the analgesic efficacy of fentanyl when added to bupivacaine for infraclavicular brachial plexus block in forearm orthopaedic surgeries. Methods: Sixty ASA I and II patients were divided into 2 groups, group B (30) and BF (30).Ultrasound guided infraclavicular brachial plexus block was performed in group B using 0.5% bupivacaine 30 ml plus 1 ml NS (total 31 ml) and in group BF using 0.5% bupivacaine plus 1 µg/kg fentanyl in 1 ml NS (total 31 ml). Onset times of sensory and motor block, duration of sensory and motor block were recorded. Results: Group BF showed a significant greater duration of sensory and motor blockade (𝑃=0.0001) than group B. Conclusions: Addition of fentanyl to bupivacaine significantly prolongs the duration of analgesia compared to bupivacaine for infraclavicular brachial plexus block.