Abstract: The paper considers the problem of development of trade and economic relations between the regions of Russia and Belarus in the context of the Union State formation. The authors prove that to fully implement international cooperation in the spheres of trade, industry, power engineering, and socio-cultural sphere, it is necessary to develop transregional interaction in the spheres of transport, communications and Media. The research object is transregional communications of the Union State. The research subject is socio-economic relations within transregional communications of the Union State. The authors apply the method of system analysis to estimate the geographical dispersion of cooperation in the spheres of transport and communications and reveal the necessity to diversify such interactions according to the geographical principle. Special attention is paid to the analysis of border territories of the Russian Federation and the Republic of Belarus. The authors prove that within the Union State, contacts and broader cooperation between the regions are connected with the difficulties of federative and unitary state structures, and offer organizational, economic, and legal measures to solve these problems. The authors consider the improvement of cooperation in the creation of transport infrastructure and the communications system as a prerequisite to the extension of innovation potential and the increase of investment potential of Russian and Belarusian regions.