PURPOSE: This study was conducted to investigate the correlation between anxiety and mastery in hospitalized young children's mothers. METHODS: The subjects were 118 mothers of young children who were hospitalized in a pediatric unit. Self-report questionnaires were used to measure the variables of anxiety and mastery. In the data analysis, SPSSWIN 23.0 was used for descriptive statistics, Pearson's correlation coefficients and multiple regression. RESULTS: The reliability of instruments were found to have a Cronbach's alpha of .84 to .92. Anxiety correlated negatively with mastery (r=-.43, p<.001) and positively with duration of hospitalization (r=.26, p=.004). In multiple regression, mastery and duration of hospitalization were significant predictors of anxiety in hospitalized young children's mothers, explaining 24.0%. CONCLUSIONS: Anxiety and mastery were significant variables in hospitalized young children's mothers. A strategy of nursing intervention which decreases anxiety in mothers must be developed by increasing the level of mastery in mothers of hospitalized young children.