The importance of Ukraine as one of the most cosmopolitan countries in the world due to its "geopolitical", "strategic" and "geo-economical" characteristics has made this country one of the most important topics in the competition between Russia and the USA in the international field. The USA and the West's efforts to promote Western values ​​and the promotion of democracy in Ukraine, Ukraine's membership in NATO and the European Union, are all indications of the effort to remove this country from Russia's orbit. Therefore, since each of the two sides act in a different manner, no end to the current conflict between Russia and the West led by the USA can be envisioned and expected. In such circumstances, and in consideration of the recent developments, the question arises whether defensive realism can explain Russia's foreign policy towards the crisis in Ukraine or not? It seems due to factors such as overall strength and power, geographical proximity, offensive power, and aggressive intentions, defensive realism is capable of clarifying and explaining Russia's foreign policy in regards to the Ukraine crisis.