Within the framework of the article, a definition of the concept of “demographic behavior of migrants” is formulated through a theoretical analysis of its semantic content. It is emphasized that it is conditioned by interaction with a foreign cultural environment, which imposes specifics on demographic behavior strategies. The peculiarities of the marital, reproductive and self-preservation behavior of migrants, primarily from the countries of Northern Eurasia to Russia, were revealed. While studying marital behavior, foreign marriages and mixed unions were distinguished. Reproductive behaviour was also studied from this perspective, including a comparison of the number of foreign mothers and fathers, as well as territorial specifics. Self-preservation behavior is considered from the perspective of the difficulties that migrants face. Based on the results of the theoretical analysis, a thematic definition of the concept under study was formulated. It is proposed to consider the demographic behavior of migrants as a set of marital, reproductive, family and self-preservation attitudes and practices influenced by the culture of the country of origin, the institutional environment of the host society, the status and degree of adaptation of the migrant. The materials use secondary statistical and sociological research data. The formulated definition and description of the structural elements of migrants’ demographic behavior can be used as a theoretical basis for developing empirical studies on this topic.