Background: Spinal anaesthesia, which is one of the techniques for infraumbilical surgeries, is most commonly criticized for limited duration of postoperative analgesia. Several adjuvants have been tried along with local anesthetic for prolonging the duration of analgesia. Aim and Objective: To evaluate and compare the post-operative analgesic effect of hyperbaric bupivicaine and hyperbaric bupivicaine plus neostigmine and assess the duration of analgesia, cumulative analgesia and time of rescue analgesia. Methodology: The study was conducted in the Department of Anesthesia, Santosh Medical College and Hospital, Ghaziabad, U.P. from December 2013- july 2014. The patients were randomly assigned to one of the two groups with 30 patients each. Allocation into groups was done by using sealed envelopes. Group A received intrathecally 2.5 ml of 0.5% of hyperbaric bupivacaine plus 1ml of normal saline. Control Group B received intrathecally 2.5ml of 0.5% hyperbaric bupivacaine plus 50 mcg of neostigmine (1ml) - Study Group. Result: The mean VAS score in the control group remained zero for 45 minutes after the drug administration, whereas it remained zero for 90 minutes in the study group. The control group's mean VAS score at 180 minutes was 1.03±1.129, while that of the study group was 0.43±0.679 statistically significant was (p value= 0.014). Conclusion: We found that use of intrathecal hyperbaric bupivicaine as adjuvant with the local anesthetic in spinal anaesthesia significantly increases the duration of analgesia (median 320 min versus 220 min) and motor block (median 255 min versus 195 min) but decreases the incidence of postoperative nausea-vomiting (PONV).