The article deals with current issues of trade and economic relations between Ukraine and its largest partner – the Russian Federation in the context of foreign economic security. The shaping factors (natural geographic ones, geopolitical location, historical, ethnic and demographic similarity of the countries, commonality and uniformity of problems and interests, equality and complementarity of the economies, the presence of diverse scientific relations) and the main features of trade and economic relations between Ukraine and Russia (basing the relations on inherited specialization and cooperation, structural asymmetry of trade relations, a high level of exports and imports dependence) are clarified. The assessment of the foreign economic security of Ukraine in the context of relations with the Russian Federation is given using the indicative method by comparing the actual values of the indicators of the state of the country’s foreign economic ties with their threshold values. On the basis of the analysis of the key indicators (the share of the RF in the total volume of trade of Ukraine, the ratio of exports coverage of imports, the ratio of exports to GDP, the ratio of imports to GDP, the share of energy resources imported from Russia), we conclude about the critical dependence of Ukraine on Russia as the main trading partner, the increase in the negative balance of foreign trade, the exports and imports dependence, the critical dependence of Ukraine on Russian energy resources. Measured in both individual indicators and the complex index we define the state of foreign economic security of Ukraine in relations with the Russian Federation as critical. The trade wars between Ukraine and Russia are studied as a threat to foreign economic security. Hereby we emphasize that they are caused not only by the nonconformity of Ukrainian goods with certain standards and the protection of Russian producers, but also by the factors of pressure on Ukraine due to the desire to control Ukrainian GTS, the rejection of certain political decisions of Ukrainian authorities, the desire of the RF to drag Ukraine into the Customs Union, lobbying of the interests of Russian producers and other economic and political motives. We suggest possible ways to secure foreign economic security. We pay attention to the development of a defence strategy that would include: a system of countermeasures in response to Russian trade and economic attacks; introduction of energy-saving programs, the rationalization of the use of energy resources while searching for alternative sources of their involvement; differentiation of exports flows of Ukrainian goods to reduce dependence on Russian market; maximization of the benefits in the fields of special Russia’s interest (Ukrainian GTS, food market).