Purpose: The purpose of this study was to examine the mediator role of psychological empowerment in the relationship between professional self-concept and burnout in psychiatric nurses. Methods: A cross-sectional correlational survey was conducted in S city and G province with 127 psychiatric nurses working in mental hospitals. Data were collected from March 8 to 16, 2012. The instruments used were the Psychological Empowerment Questionnaire, the Professional Self-concept of Nurses Instrument, and the Tedium Measurement. The collected data were analyzed using t-test, ANOVA, Pearson correlation coefficients and multiple regression with PASW 20.0. Results: Statistically significant relationships were found among professional self-concept, psychological empowerment, and burnout. Psychological empowerment functioned as a mediator between professional self-concept and burnout. Conclusion: The implication of the results is that interventions that focus on psychological empowerment will contribute to the reduction of burnout in psychiatric nurses. This study also contributes to knowledge about the conditions that precede burnout, and shows the important role of psychological empowerment in the relationship between professional self-concept and burnout.