Objectives The purpose of this study was to identify the importance of goodness of fit in mother-child temperamental interaction (MCTI) and the child problem behaviors. Methods The behavior problem of 180 child outpatients from traditional Korean medical clinic was measured with Korean version of Child Behavior Checklists, and the temperament of child and their mother was measured with Junior Temperament and Character Inventory and Temperament and Character Inventory-Revised-Short. The MCTI was calculated as the difference of the temperament score between mother and child. The correlation and linear regression analysis was performed to examine the effects of temperament on Child Behavior Checklists. Results The MCTI on Harm-Avoidance was the significant factor for explaining the internalizing problem (B=-.154, t=-10.130, p<.001), externalizing problem (B=-.045, t=-3.340, p=.001) and total problem (B=-.298, t=-7.574, p<.001). We also confirmed that the temperament of mother and child significantly correlated with the child behavior problems as provided previously. Conclusions These results showed that the temperament interaction between mother and child is an important factor for predicting problem behaviors in child clinical sample. The goodness of fit in MCTI and problem behavior should be considered as pivotal element in traditional Korean pediatrics.