PurposeDisasters and major incidents demand a multidisciplinary management. Recent experiences from terrorist attacks worldwide have resulted in a search for better assessment of the needs, resources, and knowledge in the medical and non-medical management of these incidents and also actualized the need for collaboration between civilian and military healthcare. The aim of this study was to evaluate the impact of the civilian–military collaboration in a Swedish context with the main focus on its non-medical management.MethodAn exercise, simulating a foreign military attack centrally on Swedish soil, was designed, initiated, and conducted by a team consisting of civilian and military staff. Data were collected prospectively and evaluated by an expert team.ResultsSpecific practical and technical issues were presented in collaboration between civilian and military staffs. In addition, shortcomings in decision-making, follow-up, communication, and collaboration due to prominent lack of training and exercising the tasks and positions in all managerial levels of the hospital were identified.ConclusionCurrent social and political unrests and terror attacks worldwide necessitate civilian–military collaboration. Such collaboration, however, needs to be synchronized and adjusted to avoid preventable medical and non-medical consequences. Simulation exercises might be one important source to improve such collaboration.