Each year approximately 14 million Europeans travel to developing countries in Africa, Asia, and Latin American as well as to infrequently visited countries in eastern Europe. Without protection, travelers develop symptomatic hepatitis A at the rate of 3 cases per 1000 people per month of stay. Those who eat and drink under poor hygienic conditions have an even higher risk, 20/1000/month. Studies show that hepatitis A is the most frequent vaccine-preventable disease in travelers to developing countries. Immunity to hepatitis A virus is infrequent among northern European travelers, except for those born before 1945, with a history of jaundice, or who lived for > 1 year in a developing country.