Urbanization processes are accompanied by economic concentration of resources in functional urban areas. At the same time, the level and dynamics of economic concentration differ depending on type, structure, location and national specifics of urban areas. The purpose of this article is to study economic aspects of urbanization and to develop the methodology for ranking functional urban areas by the level of their economic concentration. The survey is based on the rating approach, which is represented as a comparative analysis of indicators of economic concentration, followed by further definition of an integral indicator that helps us to rate urban areas. The results of urban areas ranking and grading by level of their economic concentration show that the highest level of economic concentration is found in Large metropolitan and metropolitan FUAs, which economic activities are dominated by financial services, as well as high-tech industry. The results of this rating can be used to justify directions of regional policy of polycentric development regarding regulation of scale of economic concentration in functional urban areas. It will also have a positive impact to effective distribution of resources within "center-periphery" economic space.