The phytosociological research of the oak forest vegetation was carried out in the northern part of the Štiavnické vrchy Mts (Central Slovakia) using the standard Zürich-Montpellier approach. The data set consisting of 41 phytosociological relevés was obtained by the authors in two vegetation seasons in 2008 and 2009. The numerical classification and the ordination methods were applied to determine the main vegetation types and to explain the structure of the vegetation-environmental data matrix, respectively. Four associations within two classes were distinguished: