SUMMARY
The purpose of this study is to identify and describe the trans-boundary economic interactions and crossborder development of the regions in various organizational forms of cooperation as a direction of globalization of the regional economic systems. Study of transformational processes in the national economy from the perspective of regionalization of social development opens up a list of scientific problems that are already urgent today and in the future will require new or additional justification. First and foremost, they include justification of the content and essence of economic regions, which operate outside the common market of the state and which are open for other national systems of the world economy within the framework of the interregional cooperation. Practice shows that territorial and economic systems are not limited to political and administrative boundaries but are able to function beyond their borders. This tendency needs scientific and theoretical justification in the meaning of a new paradigm of regional development. Methodology. The methodological basis for the study of theoretical and practical aspects of the functioning and development of regional economic systems in the conditions of interregional cooperation is the modern theories and concepts of regional development, including transborder cooperation. Practical implications. Modern publications do not adequately and deeply consider the issues of the nature of emergence and organization of regional communities’ international interactions, peculiarities of the forms of organization and economic feasibility of their existence. The essence of the research lies in justification of the scientific concept of development of the regions’ cross-border interaction as the objective tendency synthesis of the state and regions in the implementation of the extended economic reproduction. The article deals with the theoretical and practical issues of the regional economic communities’ development in the trans-boundary space of Ukraine. The terminological concepts “national economy” and “economy of Ukraine” are distinguished. And the necessity of promoting for Euroregions creation, expansion of cross-border cooperation was established. Value/ originality. It is established that the modern development of the world economy is based on the interaction of the border regions, which in total provide the cross-border movement of goods and services in the globalized economy.