Earthquake is a natural phenomenon, which is catastrophic and unpredictable in terms of time and place. Other catastrophic natural phenomena are forest fires, floods, volcanic eruptions, etc. The State, in response to its citizens' obligation to protect, is preparing appropriate Action Plans to mitigate the degree of Risk. In Greece, the responsible body is the General Secretariat for Civil Protection, assisted by the Armed Forces of the country and other agencies. The purpose of this paper is to present the degree of preparedness of the Armed Forces in the management of Natural Disasters through the "XENOKRATES" and "DEFKALION" projects and to make an overall assessment of their contribution for the period 2012-2017. Among the research questions that the work aspires to answer are Operational Planning of the Armed Forces in dealing with Disastrous Natural Phenomena, as well as their effectiveness for 2012-2017 period’s events. In this context, it is important for all Civil Protection Agencies to implement the Disaster Management Cycle, which is essentially a schematic representation of all the measures and actions of a society to protect it against natural disasters. In Greece, the Earthquake Planning and Protection Agency is the responsible body for designing, developing, coordinating and monitoring the work of educating and informing the population and executives of various public bodies regarding seismic protection and emergency response, which are urgently needed, seismic events. On the other hand, the General Secretariat for Civil Protection, in the framework of planning and development activities, is preparing plans and circulars, and is also issuing guidelines in order to properly inform the Civil Protection Agencies who assist its work. Regarding the Declaration of an Area in Emergency Situations, the Secretary-General for Civil Protection shall be the competent authority for this purpose. Emergency Response Operations Coordination Bodies include, inter alia, the Unified Coordination Center for Fire Brigades, the Center for Civil Protection Operations, and more. The XENOKRATES Master Plan for Civil Protection seeks to establish a system of effective response to disasters, with the aim of taking actions by appropriately pre-selected forces aimed at protecting life, health, citizens' property and the protection of the environment. In the context of the above, the General Staff of the National Defense exercises the overall control and coordination of its departments, while approving and coordinating the deployment of specially trained departments, as well as instruments in Civil Protection operations. On the other hand, the DEFKALION Sections Plan is a second Civil Protection Plan, which provides for, regulates and determines the assistance of the Divisions in dealing with Natural Disasters. Accordingly, it is foreseen to deploy and deploy Emergency and Domestic Emergency Situations both at home and abroad upon request from the affected country. The occurrence of Natural Disasters in Greece is a common situation, with a plethora of events involving a variety of phenomena. The overall assessment of the contribution of the Armed Forces to Personnel, Materials and Resources in the most significant of the 2012-2017 Natural Disasters is significant. Indicatively, it is reported that in 2017 in the Greek Territory a total of 95 seismic vibrations were reported, above 4R, compared to 71 in 2012. Similarly, in the case of Forest Fires, in 2017, 178 events were reported, compared to 343 in 2012. Finally, regarding the flood events of that period, 70 incidents were observed in 2017, compared to 80 floods in 2012. The contribution of the Armed Forces was decisive and significant, particularly in the provision of air extinguishers for fire engines, mechanics and vehicles, or/and lightweight type, to repair flood and earthquake damage. The total number of military personnel involved in Civil Protection missions amounts to thousands. On the other hand, Civil Protection at the international level has been effectively organized, both at the level of International Organizations and States. The European Union has appropriate Civil Protection Mechanisms to deal with Natural and/or Technological Disasters, while facilitating and coordinating the assistance provided by Member States. Similar structures of Civil Protection have to be demonstrated by the UN and NATO. Bilateral or multilateral States agreements reinforce existing Civil Protection mechanisms in personnel and media so that the international community's response to natural disasters remains high. From the conclusions of the paper, it is concluded that the structure of the Civil Protection System of the country is both effective and flexible, depending on the current situation and the rate of development of the catastrophic phenomenon. On the other hand, it is estimated that the Operational Planning of the Armed Forces of the country, based on the "XENOKRATES" and "DEFKALION" Plans, is as effective and flexible as the existence of plans, from the time of usual readiness, the detailed content thereof both in the composition of the intervening parts and the alleged materials and means of operation, the determination of the Units and Formations from which they are formed, the planning of their dispersion with a view to, as far as possible, with A better and more effective geographical coverage of the country, as well as compliance with timing and activation stages, support this view. Finally, regarding the contribution of the Armed Forces of the country to the Emergency Response, based on the “XENOKRATES” and “DEFKALION” Plans, for the period 2012-2017 and although this could be considered effective, it is estimated that the data cited above, argue that, to the extent that they were required to assist in the natural disasters of the period in question, in conjunction with the main task of the National Defense Authorities, in the context of National Defense and their other obligations (National and International), the same period, was completely successful, since the response was a high priority, both in their leadership, and the staff tried to safely, where appropriate, catastrophic events.