The Swiss Federal Office of Public Health and the Advisory Board on Immunisation recommended that all adolescents aged 11 to 15 should be vaccinated against hepatitis B in December 1997. The introduction of universal immunisation is justified for epidemiological and economical reasons. Universal immunisation in no way excludes the immunisation of all persons exposed to a specific risk and the prenatal screening and immunisation of exposed newborns. Hepatitis B vaccines are safe and highly effective. The main reasons for this recommendation are summarised in the article.