The object of study: the processes of regulation of mountain areas development that are complex socio-natural and eco-economic subsystems of the region. Objective: developing of theoretical and methodological, scientific and methodological foundations of sustainable economic, social and environmental development of mountain areas through modernization and diversification of their economies. Methods: abstract, logical, monographic, systematic, dynamic, index and economic-statistical, grouping and surveillance, method of age shift, comparative, graphic, economic and mathematical. The novelty: for the first time proved the concept of systemic socio-economic transformation in mountain areas as complex, socialized, multi-functional subsystem of the region, including environmental, social and economic components, developed a typology of mountain areas, which conducted by the criteria of social and economic development, resulting in allocated three types of spatial economic formations (adapted, depressed and backward) and the proposed system-forming parameters of economic activity and the relevant principles of state individual and targeted policies to support the concept of socio-economic modernization mountain areas as multifaceted process, methodical approach to evaluating the potential development of mountain areas including the assessment of economic, social and environmental potential, proposed methodological approaches to diversification of the economy of mountain areas as a key instrument of modernization, providing movement from monofunctional to multifunctional diversified economy. Scope: in the activities of the Committee of the Verkhovna Rada of Ukraine on Human Rights, National Minorities and International Relations in the preparation of information and analytical materials for the parliamentary hearings "State of human rights in Ukraine" and "Ukrainian labor migration: state, problems and solutions", Department of Economy of the Ivano-Frankivsk Regional State Administration in developing the socio-economic development of the Ivano-Frankivsk region in 2013 and proposals to the state program of sustainable development of the Ukrainian Carpathians as a constituent part of the European Union Program "Carpathian space", Chernivtsi Regional Council in the process of development the program of economic and social development of the Chernivtsi region in 2015, Complex program of construction, reconstruction and modernization of social infrastructure up to 2015 and the Integrated program "Local development oriented on community-III" in 2015-2018 in the part of proposals of policy on sustainable development of mountain areas.