AIM AND OBJECTIVES: - To Compare the Post Operative Anaglesic Effect of Two Different Doses of Magnesium Sulphate as an Adjuvant to Levobupivacaine in Subarachnoid Block for Inera Umbilical Surgeries Study Design: Prospective, randomized, double blind study. Background: Hyperbaric bupivacaine 0.5% is commonly used in spinal anesthesia, but its use may pose risks of sudden cardiac arrest and hypotension due to sympathetic blockade. Isobaric levobupivacaine is preferred for its lower cardiovascular side effects and central nervous system toxicity. Intrathecal adjuvants like magnesium sulfate are used to enhance postoperative analgesia without significant motor or autonomic blockade. Material and Methods : Ninety patients were randomly assigned to three groups: Group A (levobupivacaine 15mg + 100mg magnesium sulfate), Group B (levobupivacaine 15mg + 75mg magnesium sulfate), and Group C (levobupivacaine alone). Onset and duration of sensory and motor blockade, duration of postoperative analgesia, and side effects were compared. Statistics: The data analysis was carried out with ANOVA and Chi-square test using the SPSS software version 26.0 Results: : The mean duration of postoperative analgesia was similar between Group A (239.67±11.89) and Group B (236.27±6.58), both significantly longer than Group C (179±7.16). However, the visual analog scale (VAS) score at 2 hours postoperatively was higher in Group C (7.9±1.37) compared to Group A (4.5±0.93) and Group B (5.8±1.83). Conclusion: Magnesium sulfate as an adjuvant to isobaric levobupivacaine prolongs postoperative analgesia, with 100mg being the optimal dose