In this research we ask whether churches and religious organizations in postcommunist countries can contribute to social capital formation among young people. We investigate this relationship by an innovative research design that combines quantitative and qualitative methods and is firmly grounded in the comparative empirical research tradition. First, we analyze multinational survey data in order to explore the multifaceted relationship between religious participation and social capital. Second, we conduct 4 critical case studies that allow us to explore in-depth the mechanisms through which religious participation can be conducive to social capital. We consider religious participation to include both activities organized within churches and within religious nongovernmental organizations. The first pair of case studies forms a comparative investigation of the potential that churches and religious organizations has on social capital creation among the youth in Poland and Romania – the two most religious and religiously homogenous countries in East Central Europe, one Catholic and one Orthodox. The second pair of case studies follows the same logic, but focuses on how churches and religious organizations lead to social capital creation among the youth in the largest migrant communities of Romanians in Spain and Polish in the United Kingdom respectively.