In 94 our of 2570 individuals vaccinated against tick-borne encephalitis (TBE) with FSME-Immun the level of IgG antibodies to TBE virus were tested. The examination was performed before and 2.5 years after the first dose of full cycle vaccination, which according to the manufacturer, consists of three doses. The maintenance of specific seroconversion was detected in 91.9% of the studied subjects. No statistically significant differences in antibody levels were found in the different age groups. None of the immunized subject developed TBE up to the present time.