The species diversity and spatial distribution of free-living heterotrophic flagellates were investigated in soils, ground mosses and lichens of the northern taiga, southern taiga and forest steppe of European Russia and Western Siberia. Eighty-three species and forms of heterotrophic flagellates were identified. The species diversity of the cercomonadids, euglenids and kinetoplastids was the highest. Agitata tremulans, Protaspa simplex, Phalansterium solitarium, Bodomorpha minima, Spumella spp., Cercomonas spp., Neobodo designis, Spongomonas uvella, Cercomonas angustus, Paracercomonas crassicauda, Hyperamoeba dachnaya, Paraphys-omonas spp., Petalomonas minuta, Phyllomitus apiculatus, Protaspa gemmifera, Spumella sp.1, Rhynchomonas nasuta, Codosiga botrytis, Goniomonas truncata, Ploeotia spp. were the most common species. The species structure of heterotrophic flagellate communities in soils, ground mosses and lichens is mainly determined by regional features (climate, type of soils) instead of the specificity of different habitats (which are essentially similar and represent thin water films and capillaries on fine-dispersed substrates) within natural zones.