Background: Brachial plexus block is one of the most commonly used regional anesthetic techniques for postoperative analgesia. Its popularity originates in part from easily palpable landmarks and relative ease of placement. A number of adjuvants, such as ketamine, dexmedetomidine, and others have been studied to prolong the effect of supraclavicular brachial plexus block. Aim of the Work: Evaluation of the effect of adding Ketamine as an adjuvant to lidocaine in ultrasoung guided supraclavicular brachial plexus block. Patients and Methods: This randomized controlled study was conducted at the Department of Anesthesia, EL-Hussein Hospital, AL-Azhar university on 60 patients of ASA physical status I-II of either sex aged 18- 60 years. They were randomized into two equal groups 30 patients in each. Group A (Ketamine group): received 5 mg/kg lidocaine 2% and 2 mg/kg ketamine in a total volume 30 cc. Group B (Control group): received 5 mg/kg lidocaine 2% and saline in a total 30 cc. Results: the study showed a significant increase in mean control group compared to ketamine group according to postoperative VAS. Conclusion: Using of ultrasound led to decreasing the complications of supraclavicular brachial plexus block and adding ketamine as an adjuvant to lidocaine decreased the postoperative pain and the need for analgesics, without significant adverse effects. Therefore, it could be considered as an option to enhance the analgesic effects of the brachial plexus block.