The article deals with the results of an empiric research of ethnic affiliation held among Moldovans, Russians, Ukrainians, Gagauz and Bulgarians. The research aimed to study dynamics of need in identification with the in-group during the period of social transformations; it was carried out in the period of 2004-2013. The results showed that in all of the age groups of Moldovans (high school students, young people, adults) there consistently dominate the ethno-affiliative motifs. The groups of ethnic minorities (Russians, Bulgarians and Gagauz) orient themselves on ethnic group as well, but there are differences in affiliation in dependence on the age group. The group of Ukrainians showed tendency of self-orientation, most significant at the high school students. The research of ethnic affiliative motifs dynamics allows diagnosing of interethnic relations and the process of ethnic self-determination in different groups.