The purpose of the article is to justify theoretical positions and methodical aspects of functioning and development of the agrarian sector in conditions of the geo-economics paradigm. Research methods. The methodological basis for the research is principles for the systematic approach to cognition of complex open systems, which include the agricultural sector of the economy. In the research process have been used the following methods: analysis for identifying components of geo-economic agrarian business systems and interrelations between them; comparisons for identifying features of globalization, localization, and globalization in geo-space formation processes; abstraction for justifying abstract concept of geo-economic system; concepts’ operationalization for justification of definition of the economic category “geo-economics”; functional modelling for building a structural model of agrarian geo-economic system. Research results. The article suggests the definition of “geo-economics”. The system analysis of the process of agrarian geoeconomic systems’ functioning has been made, the functioning optimality criteria of which are maximum of competitiveness and fractions of world income, and minimum transaction costs, as well as provision of national security. The article substantiates basic regulations between processes of globalization, localization and glocalization in modern economic relations. It has been worked out a structural scheme of the agrarian geo-economic system functioning, which takes into account input (resources) and output (mentioned effects), system parameters, functional blocks of system functioning (stages of formation of added value chains), elements of environment (first of all, geographical and institutional factors), tools and regulatory mechanisms. Elements of scientific novelty. The concept of “agrarian geo-economic system” has been defined, systematic study of which creates a methodological basis for grounding and implementation of an entire system for provision effective functioning of the agrarian sector in conditions of geo-economics, taking into account principles of sustainable development. Practical significance. Content, structure and principles of the agrarian system functioning as components of the agrarian complex in conditions of geo-economics have been grounded. Tabl.: 1. Figs.: 2. Refs.: 24