The purpose of civil-military cooperation is to exchange resources and information to effectively manage different types of disasters. In this regard, civil-military cooperation in disaster preparedness should increase coherence in the area of information sharing and mutual support. The purpose of this study is to examine how cooperation between municipal institutions and the same nation’s military meets these requirements. The results presented in the article show that cooperation between municipal institutions and military personnel of the same nation is similar to civilian and military cooperation in international missions or disaster relief. This cooperation is based on a mutual understanding of the value of cooperation; willingness to cooperate and mutual support. At the same time, there are objective obstacles to the effectiveness of cooperation in disaster preparedness between municipal institutions and the military, mainly related to legal regulation, bureaucracy and hierarchy, often impeding the dissemination of information and undermining mutual trust between institutions. The study found that simplification of existing legislation, detailed planning process, information sharing during joint exercises and other joined activities would be important factors in improving civil (municipal)-military cooperation in disaster preparedness.