Asthma allergic rhinitis and atopic dermatitis are multifactorial disorders influenced by various familial and environmental factors. The correlation between maternal and fetal immunoglobulin E (IgE) seems to be caused by genetic factors rather than placental transfer. The purpose of this study was to evaluate and quantify the relationship of IgE levels between mothers and their offspring during the 1st year of life. Total serum IgE levels were assessed in 104 healthy pregnant women just before delivery, as well as in 104 newborns in the 1st days of life and then again at 3, 5, 6, 11 and 12 months of age. A serum IgE increase in infants during the 1st year of life is related to maternal serum IgE levels (and may be divided into three classes, according to IgE concentrations of <100, >100, and <260 kU/L), as shown by significant correlation coefficients and regression slopes. Our findings show that IgE levels in infants of mothers who presented serum IgE levels of >100 kU/L exceeded the norm during the 1st year of life, in the absence of overt atopic disease. It seems useful to consider different categories of infants, as a function of their mothers' IgE, to plan a particular follow-up for children in higher risk classes.