Purpose: This study was done to identify the mediating effect of emotional dissonance in the relationship between emotional labor and burnout among clinical nurses. Methods: A cross-sectional survey design was used. The participants were 257 nurses working at three general hospitals located in Seoul and Gyeonggi Province. Data were collected by convenience sampling using self-report questionnaires that consisted of general characteristics, and measures of emotional labor, emotional dissonance and burnout. Data were analyzed with descriptive statistics, t-test, ANOVA, correlation, and multiple regression. Results: The findings of the multiple regression were as follows. First, surface acting of emotional labor showed significant positive effects on emotional dissonance and burnout. Second, when surface acting and emotional dissonance were entered into the regression model at the same time, surface acting showed an insignificant effect on burnout, however, emotional dissonance showed a significant effect. Finally, emotional dissonance had a mediating effect only between surface acting of emotional labor and burnout, not between deep acting and burnout. Conclusion: Results of the study suggest that as a way to reduce burnout, nursing administrators should develop educational programs for nurses to perform deep acting of emotional labor instead of surface acting at the moment of truth.