OBJECTIVE We compared the prophylactic effects of intravenously administered azasetron (10 mg) and ondansetron (8 mg) on postoperative nausea and vomiting (PONV) in patients undergoing gynecological laparoscopic surgery under general anesthesia. METHODS We studied 98 ASA physical status I or II 20-65 years old, female patients, in this prospective, randomized, double blind study. Patients were randomly divided into two groups and received ondansetron 8 mg (group O) or azasetron 10 mg (group A) 5 min before the end of surgery. The incidence of PONV, Visual Analogue Scale (VAS) for pain, need for rescue antiemetic and analgesics, and adverse effects were checked at 1, 6, 12, 24, and 48 h postoperatively. RESULTS The overall incidence of PONV was 65% in group O and 49% in group A. The incidence of PONV was significantly higher in group O than in group A at 12-24 h postoperatively (nausea; 24% vs. 45%, p = 0.035, vomiting; 2% vs. 18%, p = 0.008), but there were no significant differences at 0-1, 1-6, 6-12 or 24-48 h. CONCLUSIONS In conclusion, azasetron (10 mg) produced same incidence of PONV as ondansetron (8 mg) in patients undergoing general anesthesia for gynecological laparoscopic surgery. Azasetron was more effective, in the intermediate post-operative period, between 12 and 24 h.