The purpose of the study is to determine the professional drivers which have the greatest influence on the international mobility of research scientists and to assess the level of attractiveness of EU Member States for researchers from other countries on the noted basis. The research paper used the case study of the European Union countries and derived the latest data on first employment permits issued to migrants, intellectual migrants and researchers from the Eurostat database, as well as sub-indices of the Global Innovation Index regarding research and development (R&D), knowledge creation, absorption, impact and diffusion. The author combined the methods of structural and dynamic analysis, correlation analysis and taxonomic analysis in the research process. The results obtained from the structural and dynamic analysis revealed that in recent years, on average every fourth migrant has come to EU countries aiming to find a job. In 2021, Poland topped the list among all EU Member States: every sixth permit was issued to migrants in this country. There is an overwhelming amount of evidence that the EU is one of the most attractive destinations for intellectual migration flows. In 2021, 85.04% of all first residence permits issued for employment-related reasons in the Netherlands were issued to highly skilled migrant. The value of this indicator for Austria was 70.32%, for Ireland it was 58.15%, and for Denmark it was 55.68%. The outcomes of the correlation analysis proved that countries with a high level of economic development prefer to issue the first-residence employment permits mainly to intellectual migrants. At the same time, competent issuing authorities in Germany, Slovakia and Hungary give priority to researchers when issuing the first permits. In order to investigate the importance of the professional drivers of researchers' migration, the author identified seven subpillars of the Global Innovation Index, which directly relate to research and development, creation and migration of knowledge. The results of the correlation analysis allowed the scholars to choose four drivers of researchers' migration, which have the greatest impact on the dependent variable (i.e. Y, which is a share of first permits issued to researchers in the total number of first-residence permits issued for employment-related reasons, %). The study defined such drivers as "Research and development (R&D)" sub-pillar, "Knowledge workers" sub-pillar, "Innovation linkages" subpillar, and "Knowledge creation" sub-pillar. Basing on these sub-pillars, together with the application of the taxonomic analysis, the paper assessed the attractiveness of EU countries for researchers from other countries. Hence, the author conducted an analysis of the differentiation of the EU Member States according to the values of the taxonomic indicator and proved a high level of EU countries' attractiveness for researchers from other countries, as the distribution of the comprehensive indicator is within 0.77-1.0. The practical significance of the suggested me...