Eighteen children with severe, chronic bronchial asthma were randomly divided into two groups. The families in one group received family therapy while the others served as a control group in a controlled family therapy study. Later the control families were also offered therapy in a before-after therapy design. All children were followed for 3 1/2 yr. Asthma symptoms, functional impairment and the use of drug (from diaries) were rated in ten different ways during eight months before and eight months after the family therapy. Improvement in the clinically most important variable, i.e. general pediatric assessment, was greater in the children in the family therapy group compared to the control group (p less than 0.05) Twelve children who received family therapy showed significant improvement after treatment concerning general pediatric assessment (p less than 0.01), clinical grading (p less than 0.05), peak expiratory flow (p less than 0.05), days with functional impairment/yr (p less than 0.05), no. of doses of inhaled Beta-2-agonists/month (p less than 0.01) and nights when Beta-2-agonists were inhaled (p less than 0.05). The children who only received conventional medical treatment showed no significant change in asthma symptoms. We draw the conclusion that family therapy may represent a valuable therapeutic tool in the management of severe asthma.