Building on the findings of the YARG project, this article examines the enduringly central role of (great) grandmothers in the religious lives and religious socialization of young adults in Russia and Poland. The article highlights the complexities involved in studying the transmission of religious beliefs and values from one generation to the next in social and cultural contexts where religious socialization was severely interrupted for entire generations, and where the religious ‘chain of memory’ to varying extents has had to be forged anew. Arguing that current theoretical perspectives on religious socialization in post-socialist contexts need to be more attentive to extended understandings of family and kin, the article focuses on the enduring influence that (great) grandmothers exert in contemporary modes of religious socialization of children and young people in Russia and Poland. In light of survey data and in-depth interviews with young adult university students in Russia and Poland, the influence of (great) grandmothers is explored in relation to three main dimensions: the inspirational, the instructive, and the supportive. The article illustrates how (great) grandmothers continue to represent a religious element in the lives of Russian and Polish young adults regardless of their own religious engagements and degrees of personal religiosity.