The spread of Islam in post-Soviet Buryatia is followed by the formation of a sociocultural group new to the local environment – a Muslim community that has already gone through several stages of its development. The forming model of interaction between the migrants and host community displays a rather high potential for positive mutual adaptation. The mosque as a kernel of the forming religious institution adapts norms of the Sharia laws to the conditions of the host society, simultaneously being an instrument of influence of the host society on the Muslim community.