We evaluated the potential teratogenic effects of vaginal and/or topical administration of clotrimazole in the large population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1992). The dataset included 18,515 case pregnancies and 32,804 control pregnancies; 7.1% of case and 7.7% of control women used clotrimazole during pregnancy. Clotrimazole use was not clearly associated with an increase in the total (fetal + birth) prevalence of any congenital abnormality group. There was, however, a suggestion that clotrimazole use was associated with a decrease in the prevalence of undescended testis (prevalence odds ratio = 0.72; 95% confidence interval = 0.54-0.95).