The emergence of the European Union (EU) as an international actor is an important development for Europeans, but also for the international community. The EU constitutes a new actor in international affairs. It goes beyond the nation state and seeks to construct a new international order based on rules. This new international actor must deal with a complex security environment, in particular in the Mediterranean region. This thesis seeks to determine how security perceptions in the region will influence the EU’s roles and responsibilities in the Mediterranean region as a new security actor. A detailed analysis of security discourse from both the EU and Southern Mediterranean shows that there are similar security concerns throughout the Mediterranean. Issues like terrorism or illegal immigration are securitised across the region, whereas issues like regional conflicts or weapons of mass destruction are considered security threats in specific areas, in particular the Eastern Mediterranean. Furthermore, security discourse also coexists with strong references to a common Mediterranean identity. This sharing of security perceptions and references to a common identity allows us to conclude that there is indeed a regional security complex in the Mediterranean. After determining the existence of a regional security complex in the Mediterranean, an analysis of the individual actors participating in the Euro- Mediterranean RSC, at different levels, was conducted. This analysis shows that the EU occupies a central role in the region as a global great power. Moreover, an analysis of the RSC in the Mediterranean region shows that it is an unstable security complex, susceptible to internal and external transformation in the medium to long term. As such, the EU could play a more substantial role in the Mediterranean, exercising greater influence to stabilise the region; leading the region away from instability and moving it towards a more institutional framework for conflict resolution. In this role, the EU will need to be more active throughout the region, especially in the Eastern Mediterranean. It must assume its position as a great power but with its particular capabilities and characteristics. The EU must then emphasise mediation and regional integration, including south-south integration in its policies towards the Southern Mediterranean.