Terrestrial isopods were studied in 10 oak-hornbeam forests in the Malé Karpaty Mts and in their vicinity. In total, seven species were recorded. Individual communities consisted from one to six species, Protracheoniscus politus and Porcellium collicola dominated in most of the studied sites. Beside the age of forest growth, the soil type and pH seems to be important environmental factors affecting the species richness of isopod communities.