In the following text, will be exposed the political historical context that influenced the Polish government to begin its rapprochement with the North Atlantic Treaty Organization (NATO). As well as the military and foreign relations changes that motivated this measure and the influence of the Copenhagen School in the construction of a regional security complex in Eastern Europe. After the end of World War II, Poland was influenced by the communist regime that promoted the Soviet Union and was an important member of the Warsaw Pact. However, with the fall of the USSR and its military alliance, the nascent Republic of Poland began a series of transformations in its security and foreign policy, which attracted the attention of NATO, thus initiating a round of negotiations with in order to have the Central European country as a member of the organization, achieving it in 1999.