The Common Security and Defence Policy, or CSDP for short, is a policy of the European Union. It started in the 1999. As an effort to achieve a certain level of integration among the defence and security systems of the Union member states. The CSDP is in itself a part of a bigger policy named Common Foreign and Security Policy or CFSP, which regulates and affects all the policies outwardly projected by the Union, but also builds and coordinates the policies of its member states to a certain degree. The CSDP is composed of a number of institutions which, like the policies itself, have been subjugated to systemic changes and transformations in the time between their creation and their role today. The ever-increasing role of the CSDP regarding the security of Europe, is placing the CSDP on the same level as the world security subjects like NATO, with which the CSDP has already formed cooperative and friendly relations, the CSDP dynamic transformation calls for a revision of relation between these two security actors. Can the CSDP establish itself as the carrier of the European security and at the same time keep its good and cooperative relations with NATO, is a question whose answer will result in the further development of the European security framework of the 21st Century.