It has been demonstrated that patients with atopic disease have anomalies of fatty acid composition, as a result of altered metabolism or abnormal incorporation of fatty acids into the tissues. In the present study, in 57 newborns 'at risk' for atopic disease, the polyunsaturated fatty acid (PUFA) levels were found to be lower in cord blood in infants who subsequently developed atopic disease than in non-atopics. In all babies, levels of arachidonic acid and dihomo-gamma-linolenic acid in sera at 1 and 3 months of age were lower than those in cord blood. These changes were more marked in children who subsequently developed atopic disease, and in those who, independently of signs and/or symptoms of atopic disease, were formula-fed. A comparison between IgE and PUFA levels revealed no significant differences at any tested time interval. In conclusion, our data suggest that in children 'at risk' for atopy, PUFA levels may be predictive of atopic disease.