Background: Supraclavicular block provides alternative way to general anesthesia for upper limb surgeries. They produce complete muscular relaxation, maintaining hemodynamic stability intraoperatively and avoidance of the risks with general anesthesia. The most important target of anesthesia is to manage the patient's pain, as we can do the surgical procedures with no discomfort, and controlling of intraoperative and postoperative pain. Objective: Our study aimed to detect how adding Mg sulphate or dexmedetomidine can improve the effect of local anesthetic in regional block (supra clavicular block). Patient and Methods: 90 patients aged between 20–75 years old with ASA I– II who were scheduled for forearm surgeries under supraclavicular block anesthesia were enrolled in our study. This Study was conducted in Sohag University Hospitals from May 2019 to April 2020. Patients were divided into 3 equal groups. Results: Magnesium sulphate had a more rapid onset of both sensory and motor block onset than dexmedetomedine and control groups. Dexmedetomidine had a longer duration of both motor and sensory block than magnesium sulphate group and control groups. Dexmedetomidine had a longer analgesic effect than magnesium sulphate group and control group. As regards rate of complications, there was no significant difference between the three groups. Conclusion: The addition of 1 ml (100 μg) dexmedetomedine or 200 mg magnesium sulphate to supraclaviculary-injected levobupivacaine improved the onset, duration and postoperative analgesia of levobupivacain