The article features the phases of the development of ideas about parts of speech in the Russian linguistics. The aim of this research is to analyze and compare approaches to parts of speech made by various Russian linguists. In spite of the fact that the classification of words into parts of speech has a very long history, going back to ancient grammars, the interest in the matter has never expired, in the Russian language at various phases of its development as well. An analytical review of fundamental studies devoted to this aspect has demonstrated that the theory of parts of speech in the linguistic science has got a distinct dialectical character. In this connection the investigation of the origin and development of Russian parts of speech is especially relevant not only for Russian linguistics, but also for the theory of language in general. As this research reveals, both the number and the status of parts of speech has changed in the process of their segmentation in the Russian language. The overview of their evolution in grammatical conceptions of Russian scientists is important as it helps to define the place of this category in the morphological system of the grammar. The theoretical significance of the article is in the revelation of study methods applied to parts of speech and their interpretation. The results of the research conducted can be used in the preparation of lectures and seminars in general linguistics, history of linguistics, history of language and theoretical grammar.