Cesarean section is one of the most common surgical procedures in Parturients. Regional anaesthesia has been considered the first choice because of several advantages over general anaesthesia. Bupivacaine is a commonly used drug but bupivacaine alone sometimes does not provide adequate duration of analgesia even with higher sensory blockade. Addition of opioids decreases side effects of bupivacaine and prolongs post-operative analgesia. The concept of post-operative analgesia is popular nowadays. Effective post operative analgesia promotes improved mother child bonding, early ambulation, discharge, greater patient satisfaction and early breastfeeding25. We have conducted this study to observe the effect of addition of different dose of Fentanyl citrate to Hyperbaric Bupivacaine intrathecally in cesarean section on duration of analgesia, onset and duration of motor and sensory blockade, hemodynamic stability, side- effects. In this study, we compared varying doses of intrathecal fentanyl 10mcg, 15mcg, and 20 mcg on clinical efficacy and side effects in parturients undergoing cesarean section under spinal anaesthesia. The parturients were allocated to three groups of 30 each. All patients received a total volume of 2.5 ml containing 2 ml of 0.5% hyperbaric bupivacaine with 0.5 ml of a solution containing either10 mcg (0.2 ml)Group A, 15 mcg (0.3 ml) Group B, or 20 mcg (0.4 ml)Group C of preservative-free fentanyl with normal saline. • Primary aim of our study was to observe the duration of analgesia. There was statistically significant difference in duration of analgesia among all the three groups. Duration of analgesia was prolonged more in Group B and C as compared to Group A. • There was no significant difference in onset of sensory block among all the three groups. Highest sensory dermatomal level was T5-T6 • There was statistically significant difference in time of sensory regression of sensory blockade to L1 dermatome among all the three groups. • There was no significant difference in time to achieve motor block of bromage score 3 among all the three groups. • There was statistically significant difference in duration of motor block among all the three groups. Duration of motor block was prolonged more in Group B and C as compared to Group A. • Intraoperative and postoperative hemodynamic parameters were comparable in all three groups and statistically insignificant. • No significant sedation was found among all the three groups. • None of the patients had hypotension, bradycardia, urinary retention, or respiratory depression like complications.