Background: The objective of this study was to examine the association between low blood lead levels of5 mu g/dL. Compared with the children who did not have dental caries, the risk of having dental caries according to blood lead level was estimated by using the zero-inflated negative binomial model. Results: The geometric mean (geometric standard deviation, maximum) blood lead level was 1.53 mu g/dL (1.57, 4. 89 mu g/dL), and 74.4% of children had a level of <2 mu g/dL. Blood lead level was significantly higher in the children with than in those without deciduous dental caries (1.59 vs. 1.51 mu g/dL), similarly with permanent dental caries (1. 65 vs. 1.51 mu g/dL). After adjustment for covariates, deciduous teeth surfaces that were decayed and filled increased significantly with increasing blood lead levels in a dose-dependent manner (prevalence ratio, 1.14; 95% confidence interval: 1.02-1.27). However, the risk of having dental caries in permanent teeth was not linearly associated with the increase in blood lead level. Conclusions: In the sum of decayed and filled surfaces, we found a significant increase in risk of dental caries of the deciduous teeth with an increase in blood lead levels (<5 mu g/dL) but found no statistical significance in the association with decayed and filled surfaces of caries separately.