Educational self-management programs for children with asthma have now become a routine feature in the management of the disease, as international guidelines underline. We designed this trial to find out whether Aironet, an educational program developed for children with asthma, influenced asthma severity and improved parents' knowledge of the disease. In a multicenter, prospective, randomized controlled trial we enrolled 123 children, 72 boys, mean age 8.78 yr (+/-2.33 s.d.), with intermittent or mild persistent asthma. Participants were randomly assigned to an education group, who received Aironet at baseline and 2 months later (60 children), or to a control group who did not (63 children). Follow-up lasted 12 months and included out-patient clinic visits and spirometry at 2, 4 and 12 months. At baseline and at 12 months follow-up, parents were questioned about their knowledge of asthma, and their children's asthmatic attacks, use of systemic corticosteroids, family physician or hospital emergency room visits, hospitalizations and asthma-related school absences. Questionnaire replies at 12-month follow-up reported significantly fewer asthma attacks in patients who received the program than in those who did not (1.65 +/- 1.21 vs. 2.34 +/- 1.73; p < 0.05). For the subgroup of children who had > or =3 asthma attacks at baseline, parents' knowledge improved significantly more in the educational group than in the control group. The out-patient educational program Aironet reduces the number of asthma attacks in children with intermittent or mild persistent asthma and improves knowledge of the disease.