A prospective double-blind study was conducted to compare the anti-emetic efficacy of ondansetron and droperidol in preventing postoperative emesis following strabismus surgery. A sample size of 213 patients was divided into three equal groups to receive ondansetron 150 micrograms/kg (Group A), ondansetron 75 micrograms/kg (Group B), or droperidol 75 micrograms/kg (Group C). All patients received a standardized anaesthetic technique. All episodes of emesis, recovery time, and time to tolerating oral fluids were recorded. The incidence of emesis during 24 hours was Groups A and B 19.7%, and Group C 28.2%. The lower incidence of emesis recorded by the ondansetron groups compared with the droperidol group was not statistically significant. Ondansetron at 75 micrograms/kg was as effective as 150 micrograms/kg in reducing emesis when compared with droperidol. Mean time to discharge from the recovery room was 75.3 minutes (Group A), 44.4 minutes (Group B), and 41.0 minutes (Group C). The mean time to tolerating oral fluids was 356.5 minutes (Group A), 402.8 minutes (Group B), and 378.1 minutes (Group C). There was no statistical difference in discharge times from recovery or time to tolerating oral fluids in any of the three groups.