This thesis attempts to assess the security aspect of the Barcelona Process (Process), or so called Euro-Mediterranean Partnership (EMP) within the theoretical framework of new regionalism and the Copenhagen School (Security complex theory) which agrees with neo/realism, neo-liberal institutionalism and constructivism in some aspects. The end of the Cold War broadened the security agenda and new security concerns emerged. Actually, most of the so- called security threats are not new, but the perception of them by the states has changed with globalization which increased the interconnectedness and density of the interaction. Global challenges have made states more vulnerable so appreciated the cooperative interaction at regional level. Comprehensive and cooperative security approaches gained importance and led regional security partnership among states. The construction of Euro-Mediterranean security partnership is one case stemming from the high level of interdependence between the European and the Mediterranean countries. The historical ties, economic dependency, geographical proximity increased the EU’s interest towards the Mediterranean. While new regionalism enables to grasp systemic factors in the Process, the Copenhagen School permits to understand security partnership at the regional level. The rise of illegal immigration flows and religious fundamentalism in the Mediterranean as well as tension in the Middle East conflict, the Iraqi War, and terrorist attacks to the US, Algeria and recently Turkey appreciated the importance of the EMP policy and security cooperation so make this study more crucial. This study showed that the security challenges in five sectors of the security defined by the Copenhagen School are observable in the EMP’s case. Both military and non-military concerns threaten the stability and prosperity in the Mediterranean Basin. The three baskets of the EMP depict its comprehensive security approach. Having made an overview of the Barcelona Process, the thesis evaluated the security challenges in general and the thematic areas of concerns in depth. Since security cannot be defined without reference to the perceptions and security cultures of the actors, the study examined the perceptions and security cultures in the EMP. The evaluation of the EMP showed that the EMP has shown certain developments on the way for the security cooperation. However, it could not produce tangible results due to the fundamental shortcomings categorized as inter and intra-institutional incoherence, definitional/perceptional problems and multi- actor involvement in the region. The lack of institutional structures, asymmetrical relations among partners, unbalanced distribution of powers and lack of commitment of the EU are crucial problems. On the basis of all problems lie the gap between the perceptions and security culture of Europe and the Arab world. Thus, this thesis emphasizes the enhancement of inter- subjective understanding and cultural dialogue in order to improve trust and interaction among partners. The EMP is on right track to build zone of peace in the Basin, but it requires longue durée to achieve this.