Interregional economic differentiation is common in most countries. On the one hand, economic differentiation is a natural phenomenon, on the other hand, it demonstrates the inefficiency of the national budget policy. However, to develop effective mechanisms for reducing interregional economic differentiation, its objective assessment is a priority. The purpose of this study is to analyse and evaluate the socio-economic differentiation of regional development. It considers the systematisation of theoretical provisions and methodological recommendations for the analysis and regulation of differentiation of socio-economic development of regions in the system of their economic security. The method of analysis for research of structure and dynamics of differentiation of social and economic development of regions is offered. The study proves the necessity of using a set of statistical characteristics and the method of cluster analysis. The authors of the study propose a methodical approach to the calculation of a one-dimensional relative indicator of the rank spread, which shapes an idea of the distribution of economic differentiation in the middle of the economic group under study. The methods used in problems of research of structure and dynamics of differentiation of social and economic development of regions are analysed, the technique of an estimation of level of differentiation is offered. The concept of socio-economic differentiation of regions is covered. The lines of regulation of social and economic differentiation and intensification of economic security of the region are offered. In accordance with the cluster analysis and the used adaptive method of assessing the economic security of the regions for monitoring and strategic planning of socio-economic development of the region, the socio-economic development of the regions of Ukraine was studied. According to the results of the analysis, it was found that there is a considerable discrepancy in many economic and social indicators, which may confirm the disparities in regional development
