The article deals with the elements of the lexical systems of the Serbian and Russian languages in the framework of a comparative project on lexicology, one of the goals of which is to compile a modern large Serbian-Russian dictionary. Definitions of the vocabulary is based on the translation equivalence, i. e. the denotative identity of lexemes, and it is based, apart from lexical, on derivational and grammatical semantics where possible; pragmatic and cognitive-discursive component, manifested in syntagmatic realizations of lexemes, is also taken into account. The currently processed lexical corpus provides a sample for revealing some areas and peculiarities of lexical system structuring in the Serbian language in comparison with the Russian one. The vocabulary representing linguistic contrasts is grouped according to derivational-structural and lexical-grammatical criteria, relying on its formal-explicit markers. The following lexical types were found to be difficult to represent in the dictionary: specific derivational structures; diminutive word forms (nouns, adjectives, verbs), having an access to the pragmatic and discursive level; names with the semantics of feature carriers, including feminatives; adverbial syntagms, etc. In the future it is planned to compare formally equivalent multi-valued lexemes at the level of their meaning structure.