The guidelines of the World Health Organization call for immunization against yellow fever at least 10 days before travel to endemic areas. The goal of this study was to determine whether these guidelines have been applied in 2 travel clinic settings in teaching hospitals in Israel and the United Kingdom specifically for children traveling to endemic areas. Two groups of children aged 9 months to 15 years (n = 98), who were planning to travel to yellow fever-endemic areas, were evaluated regarding characteristics related to the administration of yellow fever vaccine before travel. Overall, 19 children in both clinics (19.4%; 95% confidence interval, 12.1-28.6) had received their yellow fever vaccination < 10 days before departure (no interclinic difference). Eleven of these children received the vaccine < 7 days before departure. We found that the World Health Organization guidelines for yellow fever vaccination are frequently not followed. An initiative to explain to the public the importance of vaccination well before travel to endemic areas should be undertaken.