Polybrominated diphenyl ethers (PBDEs) are of growing public health concern because of their potential toxicities which range from endocrine disruption to neurodevelopment. However, information on their exposure among sensitive human populations is limited. The objectives of this study were to determine the levels of major PBDEs in blood sera of pregnant women and their matching newborn infants. For this purpose, a total of 198 maternal blood samples and 118 matching umbilical cord blood samples were collected from four regions of South Korea in 2011, and were determined for 19 PBDE congeners. Various demographic, dietary, and behavioral characteristics were asked in a questionnaire survey. Average concentration of total PBDEs in maternal blood serum was 3.34 ± 8.42 ng/g lipid weight (lw) at delivery and 3.14 ± 7.46 ng/g lw at 6 months of pregnancy, respectively. In cord blood serum, an average of 9.37 ± 12.60 ng/g lw was detected. Among the measured PBDE congeners, BDE-47, BDE-99 and BDE-153 were most dominant in both maternal and cord blood sera. Relatively higher levels of BDE-99 were detected in cord blood serum. Strong positive correlations were detected between maternal and cord blood serum samples, indicating the importance of maternal transfer. Health consequences of transplacental exposure to PBDEs among fetuses and newborn infants warrant further investigation.