This study was conducted to compare the effects of hyperbaric bupivacaine 0.5% alone versus hyperbaric bupivacaine 0.5% + fentanyl 25mcg in spinal anaesthesia in patients undergoing LSCS. Objective: A prospective randomised comparative study, conducted to compare the onset and duration of analgesia and hemodynamic changes, side effects like nausea, vomiting, respiratory depression, shivering, pruritis, etc. if any. Method: After institutional committee approval and obtaining written informed consent. 64 patients posted for LSCS were randomly divided into two groups with 32 patients in each group. All patients were examined before the surgery and thoroughly investigated as per institution protocol and counselled about the anaesthesia and procedure. Patients were instructed to fast for 6-8 hours before surgery. Baseline blood pressure, heart rate and oxygen saturation were recorded. Lumbar subarachnoid block was performed. After confirming free flow of CSF the drug was injected. Features assessed :The time of onset of sensory analgesia at T10 segment, maximum level of analgesia, degree of motor blockade, duration of effective analgesia, hemodynamic parameters and complications. Results: Addition of fentanyl to bupivacaine can be safely administered in patients undergoing caesarean section without significant hemodynamic changes and adverse effects. It markedly improves intraoperative anaesthesia and significantly reduces need for postoperative analgesia. Total duration of analgesia with bupivacaine alone was 176.6 +/-31.9 mins versus 276.7+/- 31.4 mins with added fentanyl. Conclusion: The addition of 25 micro gram of fentanyl to 2ml (10mg) of hyperbaric bupivacaine intensified and prolonged the duration of bupivacaine induced sensory block without affecting motor blockade.