Aim: To investigate if an intervention with extra information and support in a group setting to parents of preschool children could improve adherence and clinical outcome. Methods: This is a controlled, prospective study where the parents of 60 newly diagnosed preschool asthmatic children aged 3 mo-6 y were randomized to either a control group or to an intervention that consisted of four group sessions in close connection with the diagnosis. The basic education on asthma and the written treatment plan were the same in both groups. The outcome measures were questionnaires to the parents and classification of the children according to symptoms and medication. The adherence rate and the burden of asthma were calculated with the help of diaries and weighing of the MDIs used between 12 and 18 mo after inclusion. Results: The follow-up rate was 85% after 18 mo. The parents’ presence in the sessions was around 70% , with no gender difference. The parents’ view on adherence issues improved significantly in the intervention group. In the control group, 30% had poor adherence compared to 8% in the intervention group (p = 0.015). Both the parents and the paediatricians underestimated the number of children with poor adherence. The children in the intervention group had significantly fewer exacerbation days during the last 6 mo-2.1 compared to 3.9 d/child-although they had lower inhaled steroid doses after 18 mo. An economic calculation showed that the intervention was profitable. Conclusion: This intervention resulted in an improvement in the parents’ view on adherence, in the measured adherence rates and in the clinical outcome. A: To investigate if an intervention with extra information and support in a group setting to parents of preschool children could improve adherence and clinical outcome. Methods: This is a controlled, prospective study where the parents of 60 newly diagnosed preschool asthmatic children aged 3 mo. 6 y were randomized to either a control group or to an intervention that consisted of four group sessions in the diagnosis. The basic education on asthma and the written treatment plan were the same in both groups. The outcome measures were questionnaires to the parents and classification of the children according to symptoms and medication of the adherence rate and the burden of asthma were calculated with the help of diaries and weighing of the MDIs used between 12 and 18 months after inclusion. Results: The follow-up rate was 85% after 18 months. The parents ’presence in the sessions was around 70%, with no gender difference. The parents’ view on adherence issues improved sig In the control group, 30% had poor adherence compared to 8% in the intervention group (p = 0.015). Both the parents and the paediatricians underestimated the number of children with poor adherence. The children in the intervention group had significantly fewer exacerbation days during the last 6 mo-2.1 compared to 3.9 d / child-although they had lower lower inhaled steroid doses after 18 mo. An economic calculation showed that the intervention was profitable. Conclusion: This intervention resulted in an improvement in the parents’ view on adherence, in the measured adherence rates and in the clinical outcome.