The project of militarization of Federal Republic of Germany caused a feeling of anxiety in communist countries. On December 2nd 1954 during the conference in Moscow they warned Germany not to become a member of NATO. However on May 7th 1955 FRG was included in this organization. In answer to it, on May 14th 1955 the representatives of Albania, Bulgaria, Czechoslovakia, GDR, Poland, Rumania, Hungary and USSR signed "contract related to friendship, co-operation and mutual aid" in Warsaw - so-called Warsaw Treaty Organization.

The most important political body of it was Doradczy Komitet Polityczny and armed organ - Komitet Ministrow Obrony. In fact, the armies of European communist countries were under control of USSR. Zjednoczone Sily Zbrojne were founded , whose first commander was marshal Iwan Koniew. ZSZ included all armies of countries which signed the pact. There were 200 divisions of USSR and 80 of other countries. Warsaw Treaty Organization was also used for political purposes. At last it replaced Biuro Informacyjne Partii Komunistycznych i Robotniczych, which was a centre of information and co-ordination of the activities of communist parties.

The members of Warsaw Treaty Organization agreed to the USSR's armies' presence in their countries. This pact became a means of political blackmail in relations with communist countries in USSR hands.

Warsaw Treaty Organization gave the possibility of withdrawal from it. So in 1963 Albania suspended its membership in Warsaw Treaty Organization and in 1968 withdrew from it. On November 11th 1968 V Congress of PZPR started. Brezniew, who took part in it, formulated a doctrine, called Brezniew doctrine. He said that countries, which were included in this organization, had a right to use army forces in "defence of socialism".

In 1991 as the result of decommunisation of Central Europe Warsaw Treaty Organization lost its rights.