The purpose of this study was to examine the relationship between toddler’s negative emotionality, parenting behavior, and the moderating roles of mother’s personality. The participants in this study consisted of 221 mothers of toddlers (aged from 18 to 35months) in Seoul. The participants completed questionnaires on toddler’s negative emotionality, their personality and parenting behavior. The collected data were mainly analyzed by descriptive statistics, t-test, one-way ANOVA, Duncan test, Pearson's correlation and the multiple regression analysis. The main findings of this study were as follows. First, there was a significant difference in the negative parenting behavior according to the mother’s educational level. Second, relations between individual variables and parenting behavior were analyzed. As a result, number of children, mother’s age, toddler’s negative emotionality, and mother’s personality were significantly correlated with parenting behavior. Third, through the analysis of the moderating effect of the mother’s personality on the relationship between the toddler’s negative emotionality and parenting behavior, it was found that interactions between the mother’s neuroticism and the toddlers’ negative emotionality affected the mother’s warm parenting behavior. And interactions between the mother’s extraversion and the toddlers’s negative emotionality affected the mother’s rejection parenting behavior. The results of this study provide basic data to support mothers’ positive parenting behavior.