This paper addresses multinational and interagency cooperation in efforts to create expertise in the crisis management area. The focus is on using a simulation environment and conducting Computer Assisted eXercises (CAX) in order to enhance NATO-EU relations through development of military capabilities. More specifically, it is about how the EU and NATO and their Member States should pursue multinational projects and deliver the military capabilities they need and can use not only for military purposes but for crisis management in support of civilian authorities as well. Finally, it presents ongoing Bulgarian activities towards the creation of a Centre of Excellence in Crisis Management and Disaster Relief in support of the efforts of the EU and NATO to develop capabilities in areas where both organizations have the same requirements and similar shortfalls.