Objectives : The purpose of this study was to investigate the relationship between early childhood caries(ECC) and breastfeeding. Methods : Data of 670 children were derived from the Forth Korean National Health and Nutrition Examination Survey from 2007 to 2009. Demographic and socioeconomic data, oral health related behavior, and breastfeeding practice data were collected as independent variables. The ECC was used as a dependent variable. The chi-square test and logistic regression analysis were performed to identify the relationship between ECC and the other variables. Results : Multiple logistic regression analysis revealed that ECC was related with age, tooth brushing frequency, and breastfeeding practice. Conclusions : This study confirmed various risk indicators of ECC in Korean children, using Korean national survey data. Parents should begin an early and consistent mouth care regime to decrease the risk of ECC.