Background: In the present study practice of spinal anaesthesia, bupivacaine is the most commonly used drug for spinal anaesthesia. To improve the quality of analgesia mainly adjuvants have been used. Intrathecal ketamine, which is a NMDA receptor blocker, has analgesic effect at the spinal cord which is due to inhibition of dorsal horn.   Objective: To evaluate the efficacy of spinal anaesthesia with ketamine added to hyperbaric bupivacaine in lower abdominal and lower limb surgeries.   Methodology : The study is a a prospective randomized  controlled study. 100 ASA grade I and II aged between 18–60 years undergoing elective lower abdominal, urological, lower limb surgeries were selected and divided into 2 groups of 50 each. Bupivacaine group B received intrathecally 2.5ml of heavy bupivacaine and 1.0 ml of normal saline whereas ketamine group BK received intrathecally 2.5ml of heavy bupivacaine with 50mg ketamine (total 3.5ml). Parameters like onset and duration of sensory and motor block, highest level of sensory blockade, duration of analgesia vitals and side effects were assessed.   Results :The onset of sensory blockade was faster in BK group than compared to group B. Duration of sensory block and analgesia was significantly prolonged in group BK. Haemodynamic parameters were comparatively more stable in group BK.   Conclusion :Ketamine 50mg with 12.5 mg heavy bupivacaine when given intrathecally hastened sensory onset, prolonged the sensory block and improve the quality of analgesia in the early postoperative period.