The article analyses the development of EU security policies. It reveals the development of EU political cooperation and cooperation in the field of Justice and Home Affairs. Important milestones are discussed: the development of European Political Cooperation (EPC), TREVI group, the system of EU pillars introduced by the Maastricht Treaty and the changes made by Lisbon Treaty. Lastly, the latest EU policies on security are addressed and the interdependence of internal and external security aspects is illustrated. The article concludes that the development of the EU's competence in security matters began with European Political Cooperation and efforts to address terrorism, serving as a transition from an economic to a political union concerned with internal and external security. The Maastricht Treaty established the Justice and Home Affairs (JHA) pillar, enhancing EUwide security through cooperation on border controls, terrorism, illegal immigration, and judicial cooperation. The Treaty of Amsterdam and the Lisbon Treaty refined this framework, increasing the roles of EU institutions and prioritizing security coordination. The Common Foreign and Security Policy (CFSP), established in 1993, aims to preserve peace and enhance international security. The EU policies recognize the interconnected nature of threats arising to the security in the EU.