Introduction: Moral distress is one of the prevalent problems of nursing which causes stress, that leads to nurses being unable to show a proper moral function in the critical situations. Moreover, due to the stressful conditions in emergency department, caring behaviors of nurses is of great importance. This study aimed to determine the factors associated with moral distress and caring behaviors of nurses working in emergency departments in educational-medical centers of Mazandaran University of Medical Sciences during COVID-19 pandemic. Methodology: This study was descriptive-analytical which was conducted through stratified and convenience sampling, and by participation of 188 nurses working in emergency departments in 5 educational-medical centers of Mazandaran University of Medical Sciences in 2020. Data was collected through standard three-section questionnaire of demographic information, Corley moral distress and Wolf caring behaviors of nurses, and its validity and reliability was confirmed. Data was analyzed by using descriptive (mean and standard deviation, frequency and percentage) and analytical statistics (Mann–Whitney, Kruskal-Wallis, and Spearman correlation coefficient). Finding: Moral distress mean score of nurses working in emergency was 20/97±101/60 and they had 92/4% of average moral distress. Caring behavior of nurses was 8/62±101/60. Gender and marital status variables had a significant relation with caring behavior, in a way that male nurses and married nurses had a lower score (p<0.05). the relation between moral distress and caring behavior was NOT statistically significant. Final conclusion: Nursing staff must have a good command of their caring behavior so that caring will be presented in high quality, and patients and help-seekers’ satisfaction who come to the emergency, especially in COVID-19 pandemic, will be met. Thus, it is necessary that health and medical system managers provide educational programs to draw nurses’ attention to their caring behavior dimensions, especially in emergency departments. Key words: moral distress, caring behavior, emergency department nurse, COVID-19 pandemic