Purpose: The purpose of this study was to investigate the relationship between professional self-concept, role conflict and job satisfaction of emergency department (ER) nurse. Method: Data were collected from a convenience sample of 200 ER nurses who worked in one of 9 hospitals in 5cities. The instrument for this study was a structured questionnaire on professional self-concept, role conflict and job satisfaction. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficient, and multiple regression. Results: The mean score for professional self-concept was 2.52 (0.28), for role conflict, 3.37 (0.55), and for job satisfaction, 2.71 (0.35). There were significant differences on three variables according to total career, and satisfaction with nursing. There was a significant positive correlation between professional self-concept and role conflict, job satisfaction. Role conflict showed a significant negative correlation with job satisfaction. Conclusion: The results of this study indicate that the important role-related variables of professional self-concept, role conflict and job satisfaction of ER nurses are significantly related, and that as, role conflict is an important factor for job satisfaction of ER nurses, strategies to decrease role conflict need to be developed.