The results of a recent epidemiological study in Salzburg (Austria) showed that the prevalence of bronchial hyperresponsiveness (BHR) to hypertonic saline (HS) was 13.7% in schoolchildren aged 12-15 years. In the same study the prevalence of wheezing in the last 12 months was 11.9% and asthma had been diagnosed in 6.3%. To audit the relevance of these results and to offer medical treatment to children with newly diagnosed asthma, we invited all children who had had a positive bronchial provocation test (n = 99) or an abnormal lung function (defined as an FEV1 < 80% of the predicted value; n = 33) for clinical investigation. Seventy-five out of 99 children with BHR and 27/33 with an FEV1 < 80% of the predicted value attended the Respiratory Laboratory and a paediatric pulmonologist assessed the diagnosis on the basis of respiratory symptoms, physical examination and lung function test. In 26/53 children with asthma, the diagnosis was unknown. Although most children had mild asthma and normal lung function, half of these children had reduced physical activity. In 27/53 children with asthma, the diagnosis had already been known but, according to the specialist, had not been adequately treated. In 21/27 children with an FEV1 < 80% of the predicted value, this finding was clinically not relevant. The audit of the epidemiological study supported the assumption that asthma might be underdiagnosed and undertreated in our population.