Fifty-two asthmatic children aged 4 to 13 years (mean 9.6) were enrolled in this open 12-month study of budesonide, 200 mcg bid, administered by tube-spacer inhaler (INHALET, ASTRA DRACO). The aim of the study was to assess long-term safety, as well as efficacy, of budesonide in children whose asthma was not adequately controlled by their current therapy. Children attended the clinic every three months for assessment of lung function and height. In addition, an adrenal function test and routine clinical chemistry and haematology were performed. Parents completed diary cards once each week, recording the child's PEF, asthma symptoms, beta 2-agonist consumption and other medication (no prophylactic drugs or other inhaled steroids were allowed and oral steroids were used for emergency treatment only). There were significant increases in all clinic lung function tests (baseline to last visit) and in diary card PEF (first 3 months vs last 3 months). These were accompanied by decreases in asthma symptoms and use of beta 2-agonists or other medication. There was no indication that growth was affected by study treatment and basal adrenal function (basal cortisol) did not change significantly throughout the study. The adrenal response to Synacthen had actually increased significantly by the end of the study. No serious adverse events were associated with budesonide treatment. In conclusion, regular budesonide therapy was associated with a significant improvement in lung function and symptoms over one year. Budesonide was well-tolerated by the children and appeared to have no adverse influence on either growth or adrenal function.