The purpose of our study was to carry out a prospective follow-up of 114 newborns at term (including three pairs of twins), regarding clinical manifestations for atopy during the first year of life. Their IgE levels in cord blood samples, at 3, 6, 9 and 12 months of age were measured and the influence of race, sex, breast-feeding, maternal smoking, family income, month of birth, family history and personal manifestations of atopic disease were evaluated. Total serum immunoglobulin E was quantified by microparticle enzyme immuno-assay (MEIA). The study group consisted of 60 (53%) male neonates, 67 (59%) Caucasians and 47 (41%) blacks. In the clinical follow-up, 32 (28.1%) infants developed obvious atopic disease: 29 infants presented recurrent wheezing, two had cow's milk allergy and one had atopic dermatitis. Probable atopic disease developed in 12 (10.5%) infants, whereas 70 (61.4%) infants showed no manifestations. Cord blood IgE levels in infants with obvious atopic disease was higher when compared to those without (p = 0.024), with 70.97% sensitivity and 46.2% specificity. IgE levels were also significantly different up to 12 months in these groups (p = 0.0001), when the sensitivity was 82.1% and the specificity 54.1%. At this age, the IgE levels were higher in infants with obvious atopy than nonatopic disease in relation to male sex (p = 0.015), black race (p = 0.009), breast-feeding for less than 6 months (p = 0.011) and when the family income was less than three times the minimum wage (about US $300) (p = 0.006). There was no association between IgE levels and family history of atopy. We concluded that immune response for atopy was in a large degree influenced by environmental factors and serum IgE at 12 months was a good marker for identifying infants with risk of atopic disease in early life.