The article examines how the programmes of population censuses conducted in Russia between 1897 and 1937 reflected the dynamics of perceptions of major ethnocultural identities. Among the various forms of cultural identity in Russia, the most significant were linguistic, religious, and ethnic. However, the relative importance of these categories shift ed across different periods, as state priorities in promoting one or several of them evolved. The censuses of 1897, 1920, 1926, and 1937 vividly reveal transformations in this hierarchy of identities. Special attention is devoted to the incorporation of the category of national (ethnic) identity into census practices. In the Russian Empire of the modern era, an elite discourse emerged that proposed diverse interpretations of the nature of the ethnic (national): defining Russianness through its attributes — Orthodoxy and loyalty to the throne; defining Russianness through culture; and defining Russianness through notions of “race”, “stock”, or “blood”. For the broader Russian population, however, a presumption operated: Russian meant Orthodox and loyal to the throne (with the tacit implication of the Russian language). The study demonstrates that, in Soviet Russia, the significance of ethnic identity increased, facilitated both by the principle of national self-determination adopted by the new regime and by the administrative divisions, which were closely tied to nationality. It is therefore no coincidence that the 1920 census included, for the first time, a question on ethnic affiliation, framed as “narodnost” (“ethnic group”), which in the 1926 census was replaced with the term “nationality”. The analysis of the censuses conducted between 1897 and 1937 shows that the fundamental factors of ethnic identity in Russia — although not officially recognized in every period — were language and religion. The connection between language and ethnicity appears almost self-evident. The link between ethnicity and religion is less straightforward, yet despite the repression of religion it persisted, albeit muted; over time, however, in the structuring of identities (primary/derivative), religion and ethnicity exchanged their positions .