Background: Brachial plexus block is a popular and widely employed regional nerve block technique for perioperative anesthesia and analgesia for surgery of the upper extremity and supraclavicular approach is the easiest and most consistent method for surgery below the shoulder joint. Objectives: The aim of this the study was to compare the effect of Bupivacaine plus Dexamethasone versus Bupivacaine plus Fentanyl in ultrasound guided supra-clavicular approach of the brachial plexus block for upper limb surgeries as regards: Onset of the block, duration of the block, postoperative analgesia, and hemodynamic parameters. Patients and Methods: This prospective double – blinded, randomized controlled trial study included 60 patients of both sexes, scheduled for upper limb surgeries (Orthopedic and Plastic surgeries ). They were divided into two equal groups: Group 1: (Fentanyl group): Bupivacaine+ Fentanyl. Group 2: (Dexamethasone group): Bupivacaine + Dexamethasone.      The following parameters were assessed between the two groups: Sensory Block, motor block, time of block, analgesia duration and hemodynamics. Results: The current study showed that the addition of dexamethasone to bupivacaine for supraclavicular brachial plexus block leads to prolongation of motor and sensory block duration, prolongation of duration of analgesia. Onset of motor and sensory block was shorter in fentanyl group than dexamethasone group. Conclusion: The addition of dexamethasone to bupivacaine prolonged the time of block and analgesia duration longer than fentanyl. Also, the onset of block was shorter when fentanyl was added to bupivacaine.