The Tehran meeting of the leaders of the three main allied powers in World War II - the USSR, USA and Great Britain - meant a celebration of optimism for most of its participants. In particular, the Western allies placed their reliance on the prospects of this meeting. US President, Franklin D. Roosevelt, was enthusiastic about the Soviet participation in the war against Japan, building of the future world organization, as well as the Soviet agreement on a range of military cooperation projects in the Soviet Union. However, very soon a range of Moscow’s gestures and actions have hinted that nothing will prevent Stalin to revise or even sabotage in some cases any promises, if he could not obtain postwar Soviet domination of Europe. This paper argues the Soviets, taking advantage of military and political circumstances of the moment, skillfully speculated the fears and needs of the Western allies, managing to obtain a number of geopolitical and geostrategic advantages before the Yalta Conference.