The termination of the Cold War, which mark the second half of the 20th century, is i n close connection with the collapse of the Soviet Union and other socialist countries that belonged to the military pact known as the Warsaw Pact. The crisis of the real socialism also affected Yugoslavia, which was outside the blocks that divided Europe. The most sensitive area in which the first traces of the crisis arise is the sector of security and security services, both civilian and military. Manifest political and military changes have led to the development of a new security concept in Europe. One organization whose activities contribute to establishing and maintaining the necessary level of security in European countries is the OSCE. This organization has completely changed its role in the context of European integration processes, especially with Eastern European countries joining the European Union. On the other hand, our country is in the accession phase of joining the European Union, which is largely reflected in its relationship with the European institutions and organizations in the security domain. Therefore, one of unavoidable issues is the activity of the OSCE in the field of political and military dimensions of the security in the Republic of Serbia. The collapse of the Eastern bloc significantly contributed to the fact that formerly diverging interests of the OSCE now become common in order to provide a decisive response to new risks, threats and challenges. Serbia, as a country that is rapidly moving towards the European Union, is committed to the cooperation with the OSCE, especially when it comes to the reform process and achieving high standards of democracy in all domains of the society. It does this through partnership and successful cooperation, primarily with the two OSCE missions in its territory - the OSCE Mission to Serbia and the OSCE Mission to Kosovo, but also with other missions in the region. Proceeding from the fact that the consideration of the security problems requires a multidisciplinary approach, the authors decided to study the available international and regional legal instruments in this field. The paper also covers political agreements that represent a framework of OSCE activity in Europe. Therefore it is of utmost importance to draw attention to their basic elements, and general and specific importance for establishing and maintaining the necessary level of cooperation between the OSCE and Serbia.