The analysis of different species of small mammals role in immature taiga ticks feeding in Pribaikalie have been held on the base of trap-catching, parasitological and virological examination during 2004–2014. It is shown that the invasion depends from geographical place of catching, species, sex and age of the animal. The main hosts of the taiga tick larvae are large-toothed redback vole and shrews in the Irkutsk suburbs, and northern redbacked vole in the Eastern shore of lake Baikal. Important role may play large Japanese field mouse and root vole during number recession of the main hosts. Adult males and adult animals of both sexes were primarily affected by immature taiga ticks. The tick-borne encephalitis (TBE) virus antigen have been detected in 23,2 % of brain specimens. Two TBE strains have been isolated – from toothed redback vole and shrew.