Formation of regional development strategies is impossible without taking into account the disparities in the development levels of regions which affect the entire national economy. Strengths and weaknesses of the functioning of each regional economic system, favourable and negative trends in the development of regions, disparities in the development levels, should be analysed and detected. This paper is devoted to applying of fuzzy clustering methods for the purpose of differentiation of development levels of the regions of Ukraine, in order to make recommendations on using of fuzzy clustering results in shaping regional development strategies. The fuzzy clustering methods were applied to the regional economic development indicators of the regions of Ukraine in 2017. There were considered different fuzzy clustering results and clustering validity techniques. The study presents the fuzzy classifications accompanied with the cluster validity process and substantial analysis of the economic indicators. The results of fuzzy clustering allow to consider in more detail the similarities in the regional economic development levels, assigned to the same clusters, and reveal the dissimilarities between the regions assigned to the different clusters. The membership coefficients can be used as values for regulation of influence on important economic components of the regional development strategies.