[Tick fauna (Acari: Ixodida) in Poland]

20 valid species of Ixodida (3 Argasidae and 17 Ixodidae) are actually recognized as permanently existing in Poland. Cases of transferring 5 other Ixodidae were also recorded. Argasidae are nests- and burrows-dwelling species having multi-host development cycle, they are mainly synanthropic and semisynanthropic, nocturnal active, with the peak seasonal activity in the middle of summer. The most of Polish Ixodidae species are burrows- and nests-dwelling parasites, more common species are out of nest-dwelling, having three-host development cycle; they are basically polyxenic, active during the warm season of year, normally with two peaks of activity--in spring and at the end of summer, beginning of autumn; in most cases live in forests.