The aim of this study is to assess the value of the most common tests which can be used in epidemiological surveys to identify asthmatic children. We reviewed anamnestic information from a self-administered questionnaire, bronchial reactivity by means of exercise-test, bronchodilation-test with trimethochinol, carbachol-test (PD20 FEV1 was reported), cutaneous reactivity monitored by prick-test. (Data from a polycentric epidemiological study). We conclude that, while these tests are very useful in the initial study and in the further follow-up of the asthmatic child, providing also information about the possibilities of management of bronchoconstriction and its pharmacologic prevention, they show a limited value in the absolute diagnosis of asthma.