Introduction: To prolong the effect of spinal anesthesia with lesser adverse reaction various adjuvants has been used. Aim of this study is to compare the role of Fentanyl and clonidine as adjuvant to Intrathecal bupivacaine in patients undergoing lower limb surgeries under spinal anaesthesia. Material and methods: The study was conducted in the department of Anaesthesiology at Career Institute of medical,Lucknow. A total of 60 patients of ASA 1 and 2 between 20-75 year posted for lower limb surgery under spinal anaesthesia were randomly allocated into two groups (n= 30 each).It was prospective randomized study. In this study patients were divided into two group of thirty each. Group-A received intrathecal hyperbaric bupivacaine 2.5 ml +25μg Fentanyl. Group-B received intrathecal hyperbaric bupivacaine 2.5 ml+20 μg clonidine. Time of onset and duration of sensory and motor block, hemodynamics parameters and side effects recorded. VAS and the supplemental analgesic administered was also documented. Results: Both the groups were comparable in terms of onset and offset of sensory and motor blockade, where as duration of analgesia was prolonged in Group B as compared to Group A and the time for requirement of first analgesic dose is longer in Group B as compared to Group A.Complications and side effects are similar in both the groups and are not statistically significant. (P>0.05). Conclusion: We concluded that addition of Clonidine to intrathecal bupivacaine offers longer duration of blockade and post operative analgesia than fentanyl.