In this study the antiemetic effects of droperidol, ondansetron and their combination were evaluated in 160 ASA Grade I and II children undergoing surgery for strabismus, who were randomly assigned to one of four groups: Group D received droperidol 75 μg kg−1, group O ondansetron 0.1 mg kg−1, group D + O received both droperidol 75 μg kg−1 and ondansetron 0.1 mg kg−1, and group N NaCl as placebo. Emesis within the first 24 h occurred in 95.0% of the children with placebo medication, compared with 32.5% (D), 40.0% (O) and 45.0% (D + O) in the groups with antiemetic prophylaxis. The differences between group N and all other groups were significant (P < 0.001). However, there were no statistically significant differences between the groups D, O and D + O. It is concluded that droperidol (75 μg kg−1) and ondansetron (0.1 mg kg−1) both significantly reduce PONV in children undergoing surgery for strabismus. Neither ondansetron, nor the combination D+O were superior to droperidol alone.