IntroductionAt the time of disasters, hospitals are considered as one of the most important facilities which should provide emergency services continuously. The purpose of this study was to determine the functional vulnerability of Tehran hospitals in dealing with natural disasters.MethodsThis cross-sectional study was conducted in educational hospitals of Tehran University of Medical Science (TUMS), in 2013. Of all 26 hospitals, 12 hospitals were selected through single-stage cluster sampling, including six general (Shariati, Amiralam, Sina, Imam, Hazrat Rasoul, Baharlou) and six specialized (Bahrami, Hazrat-e Aliasghar, Shahid rajaie, Roozbeh, Moheb yas, Children Medical Center) hospitals. Data were collected using World Health Organization (WHO) checklist for functional indicators of safe hospitals, recommended for countries with similar climates. Data were collected through interviews with members of hospital crisis committees and direct observations. Data analysis was carried out using SPSS version 18 using descriptive statistics and Fisher’s exact test.ResultsFifty percent of hospitals in the study, in terms of functional vulnerability status, were in satisfactory condition with low level of vulnerability, 41.7% were in the moderate level and 8.3% were in a non-satisfactory condition with high levels of vulnerability. The results of Fisher’s exact test showed that there wasn’t a significant correlation between functional vulnerability and hospitals lifespan (p=0.99) and type of specialty (p=0.99).ConclusionAs this study, assesses hospitals’ main weaknesses in terms of procedures, strategies, plans, human resources, monitoring and evaluation, it is essential that each of these areas be reviewed by hospital managers separately, in order to take significant actions to eliminate their weaknesses.