Tick-borne encephalitis (TBE), the preventive measure against which is vaccination, is a disease caused by flavivirus (TBE virus). The infection is common in many European countries and in much of Central and Eastern Asia. Formaline-killed whole-virion high-purified vaccine inactivated is widely used for immunization of the population in Europe; however, the coverage of the population with vaccination greatly differs in the country where the natural foci of TBE are recorded. The exception is Austria where 88% of the population has been at least vaccinated against TBE and 58% has been regularly inoculated as evidenced by the officially recommended scheme. The present study has analyzed the efficacy of the above vaccine made in Austria in 2000 to 2006 in different age groups on the basis of documentary data on the cases of admissions for TBE among the unvaccinated and vaccinated and estimated the incidence of this disease in these groups, by taking into account the results of representative surveys. Our investigation has demonstrated that the efficiency of vaccination by the officially recommended scheme among the regularly inoculated persons is about 99% without statistically significant differences between the age groups. This result was observed after the first two vaccinations before completion of the basic course of vaccination, i.e. before the third vaccination; however, the efficiency of vaccination was substantially lower (about 95%) in the persons who had been irregularly inoculated, as shown by the records, i.e. they received the vaccine by the unofficial scheme. The findings confirm the high efficiency of vaccination of the population of Austria against TBE by the officially recommended scheme, which is shown in the prevention of about 2800 cases of TE.