Abstract: The subject of the research is the study of the particles as a category of immutable function words in modern Buryat and Bargut languages. The object of the study is a functioning of the particles as the main exponents of various semantic shades of words and sentences in Buryat and Bargut languages. The aim of this work is a comparative analysis of particles in the context of determining their content and structural-semantic characteristic on the material of Buryat and Bargut languages. The relevance of the work is due to the growing interest in questions of a deeper theoretical study of the usage of particles in kindred Mongolian languages, which include Buryat and Bargut languages. The study used a variety of methods: comparative, comparative-historical, methods of component analysis and observation. The scientific novelty of the study is due to the description and detection of particles of Buryat and Bargut languages in the comparative aspect, new information on the particles of the Bargut language is introduced into scientific circulation.The author pays special attention to the structural-semantic classification of particles in two languages taking for research. As a result of the analysis, the conclusion that particles serve for transferring various shades of meanings of strengthening the intonation of the statement, confidence, emotional excitement and the possibility of committing an action is made.