Purpose: The purpose of this study was to identify the critical thinking disposition and self-esteem of psychiatric nurses and to identify factors that influence critical thinking disposition. Methods: A cross-sectional study design was used in this study. The participants for this study were 158 psychiatric nurses from D city & C province. The instruments were the California Critical Thinking Disposition Inventory (CCTDI) and Self-Esteem Scale (SES). The collected data were analyzed using t-test, ANOVA, Pearson`s correlation coefficients and multiple regression with the SPSS/WIN 11.5program. Results: The mean scores for critical thinking disposition and self-esteem were 186.4±13.96 and 30.5±3.95 respectively. A significant positive correlation between critical thinking disposition and self-esteem explained 57% of the variance in critical thinking disposition for these nurses. Conclusion: Participants who had higher levels of critical thinking disposition tend to exhibit a positive self-concept. It is necessary to provide interventions program to improve the critical thinking disposition and self-concept of psychiatric nurses.