The importance of TBE has increased considerably since the mid 70 s in the whole of Europe and Far East. The number of registered clinical cases has risen and risk areas have expanded. For this development a number of factors are responsible ( i. e. global warming, ecological, political, social changes). Because of the high quality and immunogenicity of TBE vaccines available for children and adults TBE should not have to be considered any longer as a problem, subject to the fact that every person at risk has been vaccinated. An important prerequisite for a scientifically based vaccine application are the constant surveillance of TBE risk areas and an actual data base. Epidemiological data with respect to the expansion of risk areas and its level of risk are available covering most European countries with TBE risk and can be made available for medical purposes when travelling.