The problem of food security is extremely important for Ukraine and the world, especially in conditions of crises and emergencies. The authors studied the problems of overcoming the challenges of food security in the extraordinary conditions of russian aggression in Ukraine. The purpose of the study is to improve approaches to assessing food security and to identify institutional needs for overcoming food security challenges in the context of the war in Ukraine. Ukraine is the guarantor of world food security and provided almost 6% of the caloric content of world consumption. The study assesses Ukraine’s place in the global food security index. It analyzes the main legislation in the field of food security, emphasizes the need to adopt a strategy and other legislative acts in this area, clarifies the state of implementation of the Ukraine – European Union Association Agreement. Taking into account the developments of the Food and Agriculture Organization of the United Nations, the authors systematized and improved the system of food security indicators by building a functional scheme-model. It includes five main blocks – the level and quality of nutrition, physical availability of food, economic availability of food, food independence and market stability. The authors emphasize the importance of taking into account the ecology, natural resources and the state of the institutional environment. The study reveals the food security situation for each block and offers tools for its solution. It defines measures to increase food security and a list of indicative indicators that characterize its level.