In the context of ongoing globalization of the world economy and the increasing internationalization of public life, a progressively important place in the regional development is occupied by international labour migration. A natural consequence of these processes is an increase in the interstate migration of scientific personnel and the emergence of a specific phenomenon known as "brain drain". Our paper demonstrates that the most significant discrepancies take place in assessments, firstly, on the scale of the emigration flow of scientists and highly qualified specialists, and, secondly, in the consequences of the "brain drain" on the state intellectual security. Numerous politicized speculations on this subject in the world media make this topic particularly debated and highlighted. Our results show that this is largely due to the fact that there are too few analytical works studying migration processes and their impact on regional development. Moreover, there are no unified approaches to assessing the consequences of the "brain drain" due to the active inclusion of its intellectual potential in international migration processes in the 1990s. As a result, we might conclude that there is a lack of sufficient grounds for determining the existing risks from the "brain drain" as a threat to intellectual security and sustainable regional development.