PURPOSE The objective of this study was to identify the moderating and mediating effects of transformational-leadership in the relationship between medication error management climate and error reporting intention. METHODS Participants in this study were 118 nurses from 11 hospitals in Korea. The scales of medication error management climate, transformational-leadership and error reporting intention of nurses were used in this study. Descriptive statistics, t-test, ANOVA, partial Pearson correlation coefficient, and stepwise multiple regression were used for data analysis. RESULTS Higher transformational leadership group members had higher error management climate (t=3.88~4.64, p<.001) and higher intention to error reporting (t=2.49, p=.014). There were significant positive correlations between subcategories of medication error management climate and transformational leadership (r=.37~.51, p<.001). But error reporting intention was related to the transformational leadership (r=.28 p=.002), two subcategories such as 'learn from error' (r=.26, p=.004) and 'medication error competence' (r=.25, p=.008) of medication error management climate. Transformational-leadership was a moderator and a mediator between medication error management climate and error reporting intention. CONCLUSION Based on the results of this study, transformational-leadership promotion training program to construct medication error management climate and to improve error reporting intention should be needed.