In several countries it has been observed that there has been no further increase in the prevalence of asthma. This study aimed to look at asthma prevalence in children during the past 15-30 years in The Netherlands. Both general practice registration (Continuous Morbidity Registration, Nijmegen) and surveys of the public health service in Limburg (Southern parts of the Netherlands) were used for this purpose. The general practice registration showed that after a five-fold increase in asthma prevalence during the 1980s and 1990s a downward trend seemed to occur around the turn of the century. The public health service confirms a clear decrease in wheezing and dyspnoea in children during the late 1990s. Thus far, there has been no satisfactory explanation for this observation.