The article focuses on particular international (multinational) aspects of outlining security issues in the process of European integration from its beginnings till the beginning of the discussion on the Reflection paper on the future of european defence. The first part concentrates on the concept of security issues and approach to their solution in connection with setting up the first integration formations, mainly the „European Community of Steel and Coal“ and subsequently „Euroatom“. The special attention is drawn to developing approaches to security issues in connection with setting up the European Defence Community and the issues related to unsuccessful ratification of its founding treaty. According to the article the 1 Prof. PhDr. Vladimír Čechák, CSc., Vysoká škola finanční a správní, Praha, e-mail: vladimir.cechak@mail.vsfs.cz. 271 main causes of the problems which significantly restrict successful implementation of common security measures are diverse national concepts of security measures of a country, diverse identification of main sources of security dangers and partly also disunited assessment of international politics. One of the last but not least causes was also the far too general formulation of the founding treaty of the European Defence Community, as well as the ambiguously formulated relation with NATO as a determining security formation, the members of which the signatory countries of the European Defence Community were.