Background: Hospital and pre-hospital emergency nurses are at the forefront of disaster response. Disaster incidents continue to pose a threat to healthcare systems by exposing them to an overwhelming surge of patients.

Methods: This descriptive cross-sectional study was performed on 472 hospital and pre-hospital emergency nurses in Ardabil province, in the northwest Iran, from March to April 2021, were recruited by convenience sampling method. Data were collected using valid and reliable self-reported questionnaires, including the Emergency Preparedness Information questionnaire (EPIQ) and Triage Decision-making Inventory (TDMI). Data were analyzed using SPSS (Version 22) software using descriptive statistics, Pearson correlation coefficient test, t-test, ANOVA test, and multiple linear regression analysis.

Results: Emergency nurses' disaster preparedness knowledge was low according to the mean score of total disaster preparedness knowledge. Furthermore, multiple linear regression analysis showed triage decision-making, age, residence, disaster preparedness training, working on duty during a disaster, and training organization variables were predictors of disaster preparedness knowledge in hospital and pre-hospital emergency nurses (p < 0.05).

Conclusion: Emergency nurses who have higher disaster preparedness knowledge have higher triage decision-making skills. It is suggested that the managers of educational and medical centres and professional organizations provide favourable conditions for training and increasing disaster preparedness of emergency nurses according to their age and residence.