This paper is based on newly declassified Bulgarian State Security operational records from the last two Cold War decades on “Combating Terrorism”. It aims to reveal the organization of antiterrorist coordination in a “close monistic society”, which was the Warsaw Pact area, and to give some new evidences for the still not well known confidential contacts between the two adversary blocs' secret services before the downfall of the Berlin Wall. The Western countries antiterrorist approaches and regional cooperation served as impressive practical examples to the East European Security services on how to organize joint antiterrorist operations. Despite of the ideological and cultural division of Europe in a bi-polar world, the International Terrorism threat became a serious security challenge to both West and East European political systems.