Postmulticultural perspective to study and comprehend modernity involves a number of complex theoretical and practical issues associated with redefining the role of the nation state, international migration and cultural diversity in the context of globalization. The genealogy of postmulticulturalism in social and scientific discourse is presented a) in terms of its break with multiculturalism; b) in the logic of continuity of its basic ideas and concepts; c) in the perspective of the coexistence of projects of multiculturalism and postmulticulturalism. At present, the rethinking of the concepts of multiculturalism involves the search for its updated versions, including national ones, corresponding to the realities of the 21st century, as well as its redefinition as a global phenomenon in the context of the emergence of new migration patterns, transnationalization and reconfiguration of diasporas. The transition from multiculturalism to postmulticulturalism creates a framework to discuss old and new migration, diversity and superdiversity, relations between immigrant groups as elements of the structure of the national society and diasporas as social agents of transnational nature. Postmulticulturalism allows to establish new relations between national and transnational development lines, on the one hand, and to focus on patterns of representation of immigrant identity as multidimensional, hybrid and fluid, on the other hand. The emerging postmulticultural perspective implies both the recognition of cultural diversity and the preservation of collective national identity. Conceptualization of cultural diversity in terms of superdiversity or hyperdiversity in the postmulticultural perspective is associated with a rethinking of concepts of culture and ethnicity in sociology and social anthropology. In this case, ethnicity is not considered as a factor that determines a onedimensional evaluation of diversity. The fact that culture is becoming global, that is, a special context for the formation of meanings, involves shifting the focus from relational dimension of social life to the representation of patterns of identity and culture by immigrants and postimmigrants in the context of diversifying global mobility and transnationalization. Superdiversity associated with the new immigration (S.Vertovec) and social and cultural space of modern megacities correlates with postmulticulturalism.