This paper deals with various methods for multilingual document categorization and informs about the results of experiments in which EuroWordNet (EWN) plays the central role and serves as a fundamental problem solving tool. We describe both the algorithmic principles and the methodologies used in our classification system and consequently prove their functionality by experimental results. The aim of experiments was to verify the impact of multilingual collection on the quality of categorization and also find how thesaurus can be used to improve the classification and how the use of multilingual thesaurus can generalize monolingual version of categorization.