CONTEXT Obstetric anaesthesia during modern day practice has become challenge for the anaesthesiologist as the patients are generally young women and expecting a smooth outcome, not only in terms of the baby born but also herself. The problem of PONV has become challenging, though appear small problem, tough to control postoperatively. Many drugs have been on trial, but not effective completely. Of late the central 5HT(3) antagonists have been promising in achieving the objectives in comparison to the ones previously used. AIMS To compare the efficacy and safety of prophylactic use of intravenous Metoclopramide (10mg) and Ondansetron (4mg) in preventing incidence of PONV, in patients undergoing elective LSCS under spinal anaesthesia. SETTINGS AND DESIGN A prospective randomized single blinded study conducted after obtaining written informed consent, 100 women patients aged above 18 years belonging to ASA grade I and II scheduled to undergo elective LSCS under spinal anaesthesia were enrolled in the study. METHODS AND MATERIAL Patients were randomly divided into 2 groups of 50 each. Group-M: received IV Metoclopramide 10mg. Group-O: received IV Ondansetron 4mg. STATISTICAL ANALYSIS USED 'Z test' and Student's 't' test. RESULTS Number of episodes of emesis, nausea and retching were recorded at time intervals of 1 hr, 2 hr, 6 hr and 24 hr for all the patients in both groups. Incidence of Nausea was more in Group - M than Group - O at 1 hr and 2 hr, but was statistically significant (p<0.05) at 2 hr only. Incidence of vomiting was decreased in Group - O than Group - M, but was not statistically significant. Incidence of retching was more in the 1 hr and 2 hr in Group - M. CONCLUSION Fair to conclude that IV Ondansetron has proved a better prophylactic than IV Metoclopramide in preventing PONV for elective LSCS cases under spinal anaesthesia.