Abstract Introduction: disasters are ecological or emergency situations that are most of the organizations and institution’s potential. And the resulting to enormous financial and physical losses. Hospitals as the important health institutions should be ready before the events of sufficiently, to be able to cope with emergencies, ensuring rapid response to the incident. Based on a survey to determine the level of preparedness to deal with disasters in one of the selected hospitals in Tehran. Materials and Methods: This descriptive study was conducted in selected hospitals in Tehran. In order to prepare the hospital was used in 10 scopes by a 210-item check list that in a study made previously and face and content validity and reliability was assessed. Results: Amount of preparation of the study hospital in the department’s traffic 33.3% In the category of weak and units of acceptance, communication, education and transport, discharge respectively, with an average 41.7%, 50%, 41.2%, 46.7% was assessed average level Other areas include the emergency department, security, support, staffing and management, respectively, with an mean 66.7%, 64.7%64.3%61.9% and 68.2% which were rated as good. Discussion and conclusions: Based on the results obtained in this study showed the level of hospital preparedness is average however, due to the important role of hospitals in crisis seems most dedication of the managers to training and planning demand to increase the level of preparedness in times of crisis. 1- Master of Science in Nursing, Faculty of Nursing, Baghiat allah University of Medical Sciences, Tehran, Iran. 2- (*Corresponding author) Master of Science in Nursing, Faculty of Nursing AJA University of Medical Sciences, Tehran, Iran. Email: mr_n60@yahoo.com. 3- Assistant Professor, Faculty of Nursing AJA University of Medical Sciences, Tehran, Iran.