Tick-borne infections which are spread among population in Irkutsk region by ixodic ticks are being a focus of specialists’ attention as the natural foci of tick-borne infections activated in late 20th century. Many authors presume that the population structure of the tick-borne encephalitis virus may transform under the influence of the changes which take place in the populations of their carrier and reservoir – taiga ticks. The present paper provides for description of phenotypic variability of the taiga tick females from three districts of Irkutsk region what enables to assess the perspectives of the carrier’s population control by way of studying its morphological characters.