This prospective study, concerning ambulatory pediatric care in a Swedish county during a 1-year period shows that 24% of all visits to pediatric reception centres were due to atopic diseases. Atopy answered for a large proportion of the visits to all of the five pediatric centres whether they were located at a hospital or at a health centre. Hyposensitization answered for 59% of the visits for atopy, asthma for 39% and allergic rhinoconjunctivitis for 50%. The geographical accessibility of the pediatric reception centre influenced the frequency of visits due to diseases other than atopy but not visits due to atopy. Whether the children lived in a community with a pediatric centre or not made little difference to frequency of attendance. This is probably due to intensive information about atopic diseases in children addressed to the parents in the county. The balance between centralization and decentralization of an organization for ambulatory care of atopic children is discussed.