objective: to investgate the influence of mothers’ hepatitisa b virus (hbv) dna quantity on immunologic response of infants inoculated with hepatitis b vaccine combined with hepatitis b immunoglobulin(hbig). methods:from feb 2008 to feb 2010,128 full-term infants born in nanjing second hospital affiliate to southeast university with negative hbv dna and hepatitis b surface antigen(hbsag),together with positive hbsag of their mothers were selected and divided into three groups(a,b and c) according to their mothers’ hbv dna quantity,the control group (d) was composed of 21 infants with their mothers had negative hbsag. all groups were given the same preventive inoculation,and the concentrations of hepatitis b surface antibody(hbsab)were examined at the same time. results:the average concentrations of hbsab in groups a,b,c and d were(240.19±79.34),(248.58±57.07),(240.87±61.97) and(266.03±70.93)mu/ml in one-month infants,(155.87±97.78),(155.72±141.11),(196.90±141.51) and(175.26±105.34)mu/ml in two-month infants,and(766.86±314.27),(754.30±363.56),(687.18±326.45) and (888.68±247.83)mu/ml in seven-month infants,respectively. there was no significant difference among these 4 groups at the same timepoint(f=0.666,p=0.574;f=0.884,p=0.451;f=0.857,p=0.466,respectively). conclusion:the prenatal hbv dna quantity had no effect on the levels of hbsab in 1,2 and 7 months infants. the antibody produced in the first month after combined immunization and decreased in the second month. the immunologic response of infants was not affected by mothers’ hbv dna quantity.