Sociological surveys show that most citizens of Russia identify with specific religious traditions. At the same time, most of the surveys about religious make-up, show a big gap between the number of those who consider themselves to be believers and those who actually practice their religious beliefs (that is, attend religious services, pray regularly, and observe religious doctrines and rituals). Moreover, there are also those who do not call themselves believers but associate themselves with a specific denomination. The goal of this article is to interpret these figures and explain this apparent paradox. The author argues that these peculiarities are rooted in specific interconnections of different types of cultural identities, first of all religious and ethnic identity. The interconnection of religion and ethnicity is grounded in Orthodox doctrine itself and in the principle of autocephalous churches. But in Russia the interconnection of religion and ethnicity also has been fostered and promoted by the state. One of the state's effective levers in the construction or shaping collective cultural identities is the population census. The article demonstrates how censuses have contributed to and cemented the close interconnection of religion and ethnicity in Russia and how this interconnection has shaped the specifics of religiosity in contemporary