PURPOSE: The purpose of this study is to compare birth outcomes based on maternal ethnicity in Korea. METHODS: Using the birth data of Statistics Korea from 2010 to 2015, this study selected data from infants with a Vietnamese mother and Korean father (Vietnamese/Korean group), and a Chinese mother and Korean father (Chinese/Korean group), to compare them with that of a Korean mother and Korean father (Korean/Korean group). The newborn infants' birth outcomes and parental characteristics were investigated, and trends in annual changes were compared. In addition, this study investigated whether the mother's ethnicity affected the mean birth weight. RESULTS: Gestational age and birth weight were highest in the Chinese/Korean group, and were slightly lower in the Korean/Korean and Vietnamese/Korean group, in that order. The highest rate of preterm birth before 37 weeks and low birth weight rate were observed in the Vietnamese/Korean group; 4.62% and 4.26%, respectively. From 2010 to 2015, the mean gestational age decreased in all the three groups, and the preterm birth rate increased at gestational ages less than 37 weeks. However, the birth weight decreased only in the Korean/Korean group, but increased in the Chinese/Korean and Vietnamese/Korean groups. In addition, we found that factors such as parents' educational levels, percentage of hospital births, and appropriate maternal age improved in the Vietnamese/Korean group. CONCLUSION: This study confirms that the mean birth weight and low birth weight rate are affected by maternal ethnicity in Korea. Therefore, careful research and active national support policies are needed.