Background: Subarachnoid (spinal) block is a safe and effective alternative to general anesthesia for arthroscopic knee surgeries. Hyperbaric bupivacaine, the local anaesthetic most commonly used, don’t have the advantage of prolonged analgesia. Due to the early arising post-operative pain the role of various adjuvants has been proposed and evaluated. The present study was aimed to compare the clinical efficiency of intrathecal fentanyl with nalbuphine as adjuvant to 0.5% hyperbaric bupivacaine for arthroscopic knee surgeries.