Excretion IgE and eosinophils was assayed in the urine of 25 children with bronchial asthma during attack (I) after regression of symptoms (II) and in a group of healthy children aged 4-15 years. Three healthy children (12%) excreted trace amounts of IgE and single eosinophils to urine. In the group of sick children during attack (I), 20 children (80%) excreted IgE in urine, 10 children (40%) excreted eosinophils. Thirteen children (52%) had nocturia, dysuria or erythrocyturia of unknown cause. After regression of acute symptoms of asthma (II) IgE in urine was excreted in smaller amounts than in (I) by 60% of the children, while eosinophils by 24% children. In the II investigation, 8 children (32%) still had nocturia. It was found that IgE and eosinophils are present in the urine of children with bronchial asthma, regardless if symptoms from the urinary tract are present or not.