Malacocoenoses containing Ruthenica filograna (Rossm.), a forest-dwelling clausiliid, were studied in two localities in Poland: the nature reserve Dębno nad Wartą (Wielkopolska region) and the Valley of Pieniński Potok (Pieniny Mts). The malacocoenoses were composed of 20 and 42 species, respectively. In Dębno nad Wartą R. filograna was the most frequent and abundant species; in the Valley of Pieniński Potok the most frequent and abundant species was Vitrea diaphana. The structure of the two communities differed also in other respects. The gastropod density in the two localities was similar (168 and 185 individuals · m^–2, respectively), but their species composition was not, with only six species in common (Nei index 0.22).