The number of cases with tick-borne encephalitis in Europe has increased particularly in the 1990's, and new regions have become endemic. Ixodes persulcatus, i.e. the taiga tick, is found on the west coast of Finland along the Närpiö-Simo axis. This tick has not been encountered in other parts of Western Europe. In Kokkola archipelago it transmits the Siberian subtype of tick-borne encephalitis virus. We describe the first and fatal case of tick-borne encephalitis transmitted by the "taiga tick" in Finland.