Abstract: Objective To assess the impact of low level lead exposu re on physical development of newborns.Methods The consent informed mothers and their newborns from two hospitals in Shanghai and Dalian were selected with cluster sampling.Questionnaire survey and physical examination were carried out in the mothers and their newborns.Trace elements including Pb and Zn of both maternal and neonatal blood were assessed by biological detection.Results Geometric mean of cord blood lead(CBPb)among the neonatals of Shanhai and Dalian was 47.66μg/L and 31.08μg/L and the incidence of high blood lead(>100μg/L)was 5.23% and 3.54% in Shanghai and Dalian,respectively.No significant difference was found in physical development between the group with CB Pb higher than 100μg/L and the normal group(P>0.05),and the same as for threshold of 750μg/L.While significant differences were found in birth length and weight between the group with CB Pb higher than 50μgl/L and the normal in Shanghai(P<0.05).Conclusion There is a harmful effect of low level lead exposure(<100μg/L)on physical development of newborns.