BACKGROUND: In the present day practice of anaesthesia, bupivacaine is the most commonly used drug for spinal anaesthesia. To improve the quality of analgesia and prolong the duration of anaesthesia many adjuvants have been used namely Neostigmine, Clonidine, Propofol. The new α2 agonist dexmedetomidine has been proved to prolong the spinal anaesthesia. We hypothesized that dexmedetomidine when administered intravenously as an adjuvant to spinal anaesthesia prolongs spinal analgesia. METHODS: 90 patients of ASA grade I & II were randomly allocated into two equal groups namely Group A and Group B. Group A received 3.5ml of 0.5% hyperbaric bupivacaine. Group B received 3.5ml of 0.5% hyperbaric bupivacaine followed by loading dose of 1µg/kg of dexmeditomedine intravenously 30mins after the subarachnoid block and maintenance infusion dose of 0.5µg/kg/hr till the end of surgery. Patient in Group A received normal saline. The regression to reach S1 sensory level and Bromage 0 (zero) motor scale, haemodynamic changes and level of sedation were recorded. RESULTS: The duration of sensory block was 246.33±51.41 min in Group B as compared to Group A (176.89±34.22). The duration of sensory block was longer in Group B. The duration of motor blockade was longer in Group B than Group A (193.33±34.24 Vs 159.78±23.52). Bradycardia and hypotension was more in Group B than Group A but was not significant