Allergic diseases of school children of 6 to 12 years of age were investigated by means of questionnairs to their parents and medical examinations of children in a residential area of Tokyo in July 1964. Prevalence of allergic diseases suggested that skin symptoms were most frequent, then bronchial asthma and neurotic symptoms were marked. It appeared that allergic symptoms were associated with ones of patients' mothers. Allergic symptoms of children seemed to have no statistically significant relationships either to the grade of physical development or to study records. Causative or provoking agents were proved to be the change of atomospheric temperature, certain kinds of foods such as eggs and others. It is conclusive that allergic diseases of school children can be brought under health care program in terms of comprehensive medicine including intensive clinical cares.