Czarnocin and the surroundings meadows are located in the Skoszewskie Meadows district. These permanent grasslands, very abundant in the past, are now dominated by the sedges, reeds and phytocenosis with Reed Canary-grass, Wood Small-reed and Common Couch. These areas are still very valuable, and were included into the Nature 2000. The main aim of the protection is to increase biodiversity of flora and fauna in these areas. Till now the research has included mostly flora and avifauna. There are no records about other vertebrates’ species. In the present paper the authors tried to estimate the composition of the small mammals’ species living on this tract. The bone material, skeletonized from the pellets of the Barn Owl (Tyto alba) was used. Research results show 12 species of small mammals, including 5 protected species. A big percentage of Soricidae and Arvicolidae families are connected with environmental conditions (mostly high soil moisture) and extensive forms of grasslands management.