Objective(s): Incidence of postoperative nausea and vomiting (PONV), without active intervention, following caesarean section is very high. We evaluated the effectiveness of intravenous (IV) ramosetron in counteracting PONV up to 24 hr following caesarean section, using granisetron as the comparator drug. Material and method: In a prospective, randomized, double blind study, 100 parturient received ramoserton 0.3 mg or granisetron 3 mg (n=50 each) intravenously, immediately after clamping of umbilical cord. A standard spinal anesthesia technique and postoperative analgesia were used. Nausea, vomiting, adverse effect and overall patient satisfaction score were then observed for up to 24 hr postoperatively. Results: The incidence of a complete response, defined as no PONV and no need for another rescue medication, 0-6 hr postoperatively was 86% with granisetron and 94% with ramosetron; the corresponding incidence 6-24 hr postoperatively was 80% and 90%. No clinically serious adverse events due to the drugs were observed in any of the groups. Conclusion: Prophylactic use of ramoseton and granisetron is equally effective in reducing PONV but ramosetron is superior in reducing rescue antiemetic requirement following caesarean delivery under spinal anesthesia