This study examines the circumstances which lead to the purge of Aleksandar Ranković, the longtime person “Number one” in the State Security's apparatus. The study also analyses the impact it had on the future events in the history of Yugoslavia. The political fall of Aleksandar Ranković coincided with the beginning of the process of redefining relations between the member-states of the Federation sparkling suspicions that the two events were closely interlinked. Moreover, Aleksandar Ranković was posthumously proclaimed Serbian nationalist. In this study, we also analyse what affairs during the Ranković’s ouster can be linked to his name; how much truth there is in the accusations of his involvement in the wire-tapping of the Yugoslav top level political leaders’ affair and what were his ambitions to become one of them. What implications did these events have on the wider scope of the state’s political actions?