The strengthening of external factors and emerging crises of 2020–2022 related to the global epidemiological situation of COVID-19 and trade barriers, had a significant impact on the timely execution of foreign trade contracts, the efficiency of supply chains, environment of the global food market and the market for inputs for production agricultural products and food. At the same time, the unprecedented sanctions policy against the Republic of Belarus required a more sustainable agri-food system and the development of fundamentally new scientifically substantiated directions for diversifying export supplies. Step-by-step methodology has been developed for forecasting the development of foreign markets for agri-food products, which is a set of goals, objectives, an algorithm for conducting and an analytical product based on Microsoft Excel analysis tools, based on a set of factors impacting the trading process. In addition, a system of economic indicators for assessing the functioning of food markets and mechanisms for product access, including customs-tariff and non-tariff measures, has been substantiated. The methodology was tested based on example of the member states of the Eurasian Economic Union (EAEU) as the main trading partners of the Republic of Belarus, as well as the countries of Asia (Vietnam, Iran, China, Singapore) and Africa (Algeria, Egypt). The scientific novelty of the development lies in using a step-by-step algorithm for assessing the market situation of a particular country when making rational management decisions on the effective use of the existing potential and resources of agro-industrial complex organizations in order to enter existing and new markets (segments). These developments can be used by the Ministry of Agriculture and Food of the Republic of Belarus, the “Belgospischeprom” concern and other subjects of the agricultural business in preparation of analytical reviews of the country’s market environments for agricultural and food products.