The main idea of this work is that the role of clusters in regional competitiveness depends on the economic development stage of the concrete region. In the first chapter of the work, the origin of the notion of region and its competitiveness is studied; the theoretical and methodological basis for the process of economic regionalization is given. In its second chapter, the notion of cluster is conceptualized, and the role of clusters in regional competitiveness is empirically proven using M.Porter's, M.Enright's, D.Stark's and the World Economic Forum's methodologies. In its third chapter, foreign research and practical experience in regional economic clustering, as well as the opportunities of its application in Latvia are studied; Latvian experience of cluster formation and state support is analyzed. In its fourth chapter, cluster identification methodology in Latvia is probated, the author's approach to define an economic region is offered and substantiated, as well as the role of clusters in competitiveness of Latvian regions is determined. In addition, the author's elaborated study course „Cluster Development" for High Schools is given.