The article analyzes the data collected in four regular sociological surveys (RLMS HSE, The European Social Survey, The European Values Study and Levada Center) in order to assess the dynamics of various indicators of religiousness of young people in Russia. These indicators include subjective assessment of one's own religious belief, religious affiliation, church attendance, and religious socialization. A comparison of tools (question statement, filters) on religiosity criteria is made to determine whether different methods of questioning can lead to different assessment results. In part, we argue that this effect of filtering questions can be found in different assessments of the level of affiliated believers. Comparative data analysis generally shows a slow decline in the proportion of young people with Orthodox affiliation, although there is no similar change in the subjective assessment of religiosity. At the same time, over the past 20 years, assessments of engagement in religious practices and socialization have revealed an increasing process of differentiation of faith groups among young people. The proportion of those who have never attended a religious service among young people has declined significantly due to an increase in the proportion of parishioners on holidays and those who attend services frequently. In general, we conclude that it is possible to discuss the structural changes in the religious landscape that manifest themselves in the differentiation between Orthodox and socialized groups of believers.