Background: Many studies in past have shown that addition of clonidine (15–30 µg) to intrathecal local anaesthetic improves intraoperative analgesia and increases the duration of sensory and motor block. We conducted a prospective randomised double blinded study to evaluate the lowest dose of intrathecal clonidine as adjunct to hyperbaric bupivacaine that will produce maximum benefit with minimum side effects. Material and methods: Eighty patients of ASA grade I and II, scheduled for total abdominal hysterectomy (TAH) under spinal anaesthesia were divided randomly into four groups. Control group (Group I) received 13.5mg 0.5% hyperbaric bupivacaine. Study groups received 15µg (Group II), 30µg (Group III) and 45µg (Group IV) made to 3ml volume with 13.5mg 0.5% hyperbaric bupivacaine. Result: The mean time of onset of block was lower while duration of analgesia and motor blockade was prolonged in all clonidine groups (Group IV > Group III > Group II). The change was less significant in Group III and IV. 40% patients in Group IV and 20% patients in Group III had significant fall in mean arterial blood pressure (MAP). 60% patients in Group IV and 20% in Group III developed bradycardia. 90% patients were sedated in Group IV. Conclusion: We concluded that addition of clonidine to intrathecal bupivacaine significantly reduces the onset time of sensory and motor block, prolongs duration of spinal block with 30µg being optimum dose.