Background: Spinal anaesthesiais being used most commonly worldwide for surgeries on lower part of the body since years. Different local anaesthetic agents with different adjuvants have been studied and are in use for spinal anaesthesia. Bupivacaine 0.5% heavy(hyperbaric) has been studied along with adjuvant drugs like opioids, vasoconstrictors, alpha 2 agonists, sedatives, steroids, neostigmine, magnesium sulphate and ketamine to enhance its duration of effect. Various studies have been carried out in which hyperbaric bupivacaine either alone or with different adjuvants had been used for spinal anaesthesia. AIM: To study and compare the duration of analgesic effect of adjuvants with hyperbaric Bupivacaine in spinal anaesthesia and to delay rescue analgesic dose requirement and to study the duration of neurological recovery after surgery during postoperative period. After study of different literatures, we decided to compare effect of Dexamethasone and Ketamine as an adjuvant with Bupivacaine heavy0.5% in spinal anaesthesia. Methods: We conducted study on total 64 patients and they were divided in two groups - Group A 32 patients and Group B 32 patients. Spinal anaesthesia was given with either bupivacaine0.5% heavy+ 4mg Dexamethasone in Group A patients or bupivacaine0.5% heavy+Ketamine25mg in Group B patients using standard spinal anaesthesia technique. We noted duration of sensory and motor block and time of requirement of first rescue analgesic. Result: Duration of sensory and motor block was significantly longer in Group A patients than Group B patients(p<0.05). Time of rescue analgesic requirement was also significantly delayed in Group A than Group B.(p<0.05). Conclusion: Addition Of Dexamethasone with hyperbaric Bupivacaine0.5% causes prolonged sensory and motor block and pain free period in comparison with addition of Ketamine with hyperbaric Bupivacaine0.5% in spinal anaesthesia.