Background: In disaster situations, the elderly are considered to be a particularly vulnerable population. Preparedness is the key to reduce post-disaster damage. There is limited research in middle-income countries on how well elderly emergency department (ED) patients are prepared for disaster situations. The objective of this study was to determine the attitudes and behavior of elderly ED patients toward disaster preparedness. Methods: This study was a cross-sectional face-to-face survey at one urban teaching hospital in Bangkok, Thailand between August 1st and September 30th, 2016. Patients aged 60 and older who presented to the ED were included to this study. We excluded patients who had severe dementia [defined as Short Portable Mental State Questionnaires (SPMSQ) > 8], were unable to speak Thai, had severe trauma and/or needed immediate resuscitation. The survey instruction was adapted from previous disaster surveys. This study was approved by the Vajira Institutional Review Board (IRB). Results: A total of 243 patients were enrolled. Most of them were female [154 patients (63.4%)]. The median age was 72 [Interquartile range (IQR) 66-81] years and the most common underlying diseases were hypertension [148 patients (60.9%)] and diabetes [108 patients (44.4%)]. The majority of patients [172 patients (72.4%)] reported that they had had some teaching about disaster knowledge from a healthcare provider and had experienced a disaster [138 patients (56.8%)]. While 175/197 (81.8%) patients who had underlying diseases reported that they had a medication supply for disaster situations, only 61 (25.1%) patients had an emergency toolbox for disasters. Most patients (159, 65.4%) did not know the emergency telephone number, and 133 (54.7%) patients reported transportation limitations. Conclusions: While most Thai elderly ED patients reported having a medication supply for disaster situations, many lacked comprehensive plans for a disaster situation. Work needs to be done to improve the quality of preparedness in disaster situations among elderly patients. Future research should focus on preparedness knowledge regarding evacuation, and shelter/residence for older patients.