Abstract: Objective To investigate mercury(Hg)exposure in neonates and their mothers in Shanghai and Dalian,and to analyze related factors.Methods From September 2006 to April 2007,peripheral blood and umbilical cord blood samples were collected in 178 neonates and 110 women who delivered their babies in Shanghai and Dalian,respectively.Questionnaire survey was conducted and related factors were analyzed.Results The medians of maternal and umbilical cord blood Hg concentration were 1.35μg/L and 2.29μg/L for Shanghai,and 1.99μg/L and 3.57μg/L for Dalian,respectively.The cord blood Hg level was positively correlated with maternal blood Hg level(r=0.453 shanghai,r=0.237 for Dalian),and the Hg level in cord blood was significantly higher than that of maternal blood Hg level(P<0.01).In Dalian,there were three samples(1.7%)of maternal blood with Hg concentration exceeding USEPA's recommending reference level(5.8μg/L),and 9 umbilical cord blood samples(8.4%)with higher Hg level than the reference level.The results of multilinear regression analysis showed that passive smoking history and pesticide use at home were related to Hg level of blood samples.Conclusion For people without occupational exposure,unhealthy lifestyle and living environmental pollution are the main relevant factors for mercury exposure.