The relevance of the work lies in the fact that migration is one of the main demographic processes, which can bring both positive and negative consequences in the demographic, political, socio-economic and ethnic situation.In the framework of the research of the influence of migration factor on the ethnic component of the country, changes in the national composition of several countries are considered due to the fact that migrants daily cross the state borders, for the most part, due to labor migration. Some migrants come to work in other countries and then return to the country of emigration, while others assimilate in the country of immigration, then marry, obtain residence permits or citizenship of this or that country, then contribute to the demographic structure of the country, thereby changing the ethnic composition of the country.