The occurrence of small mammals (Eulipotyphla, Chiroptera, Rodentia) was studied in pellets of six owl species (Bubo bubo, Strix aluco, Asio otus, Tyto alba, Aegolius funereus, and Glaucidium passerinum) collected in several regions of Moravia and Silesia in 1970–2010. The analysis yielded remnants of 52,356 individuals belonging to 39 small mammal species up to size of hedgehog and muskrat. The species found most frequently were Microtus arvalis, M. agrestris, Mus musculus, Sorex araneus, Clethrionomys glareolus, Apodemus agrarius and Apodemus sp. Data obtained here complement the grid distributional maps in some species; records of Microtus agrestis, Apodemus agrarius, Muscardinus avellanarius, and Dryomys nitedula are of particular importance. Food composition of individual owl species is discussed including regional differences.