Agro-industrial integration is a classic case of vertical integration associated with ensuring the interaction of economic entities operating at different stages of the formation of the final product values in the agri-food complex. It is proposed to consider sets of incentive causes, constraints and risks, directions, types, and forms of integration as the essential characteristics of vertical agro-industrial integration. The cluster model for the integration relation development is considered the most promising form of development of agri-food systems, and clusters are viewed as the optimal tool for creating the system of inter-subject relations between participants in the agro-industrial integration interacting within the boundaries of localized economic areas. The use of the advantages of territorial concentration and the possibility of establishing strong and longterm formal and informal relations among the economic integration subjects objectively determine higher flexibility of cluster structures and the efficiency of functioning of all their elements.