A period of qualitative changes in Russia has led to the transformation of many social aspects, including the social structure. Unsurprisingly, its specific features and certain social groups and strata are of particular interest at the moment. Both the scientific community and the general public are traditionally interested in the social entity of middle class. The term “middle class”, however, does not have a universal definition. Its meaning has been changing along with the social development and social structure transformations, depending on the historical context of a society. Moreover, several conceptually different approaches to identifying the middle class were emerging separately (due to the fact that middle class analysis was based on different goals and objectives that required different methodologies). In Russia, there is ongoing theoretical debate over the necessary and sufficient conditions for classifying an individual or a household as middle-class. Arguments for existence of the middle class in the country are quite often completely different as a result of diverse approaches and respective criteria, as well as the chosen thresholds, for identifying the sought-for middle class. Differences in the methodology of middle class identification lead to a considerable spread in the estimates of its share, from 2-3% to at least half of the population. Chapter presents different approaches to middle class definition, brief history of middle class studies in Russia and main results concerning specifics of Russian middle class from different research studies.