The authors explore the evolution of American evaluation of the Partisan Detachments of Yugoslavia as well as their communist leaders' connections with the Soviet Union. The authors analyze the factors determining the US perception of the Soviet policy toward Yugoslavia, characterizing the regulating influence of intelligence data on the position taken by F. Roosevelt and the Department of State. The article discovers certain political figures and Slavic emigrant organizations' propaganda in the US supportive of Tito and his movement. Conclusions at the end of the article are made with reference to American periodicals and unpublished materials held by the funds of the Russian State Archive of Sociopolitical History, including documents of the Office of Strategic Services the USSR was aware of.