Introduction: Spinal anaesthesia is simple, rapid and most reliable anaesthetic technique. It is the most common regional anaesthesia technique, practiced worldwide. It is an efficient technique, which is easy to perform. However, associated with side effects like hypotension, bradycardia and also post-operative nausea, vomiting and chills. Decrease in vascular resistance caused by sympathetic blockade leads to drop in arterial pressure. Bradycardia is caused due to parasympathetic over activity, increase in baroreceptor activity and Bezold Jarish reflex (BJR). Ondansetron is a well-tolerated drug with 5HT3 antagonising effects which is used most commonly for peri-operative nausea and vomiting with minor side effects. Ondansetron poorly penetrates the blood brain barrier with minimal influence on central serotogenic mechanisms. Hence has less chances of causing cognitive side effects like headache, agitation and confusion. The objectives of this study is to assess the effect of intravenous ondansetron on spinal anaesthesia induced hypotension and bradycardia and the effect of ondansetron on Peri-operative nausea, vomiting and chills