AbstractPostoperative nausea & vomiting (PONV) is one of the most common and distressing complication during postoperative period increasing morbidity and cost of medical care. This study was conducted to compare the efficacy of Ondansetron with that of Ondansetron and Dexamethasone combination in PONV prophylaxis. Methodology: This prospective randomized controlled study was conducted at our institution over a period of one year where 80 patients belonging to ASA 1 & 2 who were posted for elective middle ear surgery were included. Pts were randomly divided into two groups group 1 & group 2 having 40 pts in each. Group 1 pts received Ondansetron 4 mg at the end of surgery and group 2 pts received Dexamethasone 8 mg at induction of anaesthesia and Ondansetron 4mg at the end of surgery for PONV prophylaxis. Number of epiosodes of nausea, vomiting and doses of rescue antiemetics used were recorded during 0 - 6hrs, 6- 12 hrs & 12 – 24 hrsduring the postoperative period. Results: The no. of pt who had nausea & vomiting were more in group 1 compared to group 2, but the result was not statistically significant. But no. of pts who required rescue antiemetic in group 1 was significantly higher than that of group 2. Conclusion: So for effective PONV prophylaxis combination of Ondansetron and Dexamethasone is superior to Ondansetron alone.