This study investigated the long-term effects of maternal dietary avoidance during lactation on the occurrence of atopic symptoms, development of immunoglobulin E (IgE) antibodies to food and inhaled allergens and occurrence of positive skin-prick tests (SPT) in 65 children with a family history of atopy whose mothers adhered to a diet devoid of eggs, cow's milk and fish during the first 3 months of lactation (D group) and in a matched group of 50 children with mothers not practising such a diet (ND group). The diets of the D and ND children were similar. All children attended 7 follow-ups from the age of 3 months to the age of 10 y. After the first follow-up there was a 100% retention of participants. The results of the seventh follow-up at 10 y are presented. Total IgE values and IgE antibodies to seven food and seven inhaled allergens were determined by the Phadebas IgE CAP and the Phadebas RAST, respectively. SPT were conducted for five food and seven inhaled allergens. High rates of atopic symptoms occurred in both groups, but there were no differences between the groups. Sensitization to the three foods avoided by the mothers during lactation was similar, but the overall test reactivity to foods was lower in the D group. Sensitization to inhaled allergens was similar in the two groups. During the 10 y of follow-up, there was no difference between the groups in the occurrence of indoor furred animals, tobacco smoking, changes in heredity for atopy or development of total IgE, but a higher rate of maternal sensitization was found in the ND group, as judged by a screening test for IgE antibodies to inhalants (Phadiatop). The results do not support general recommendations to implement prophylactic maternal dietary avoidance during lactation in allergy-prone families.