The hyperventilation syndrome is a disease affecting children as well as adults. It predominates in female and may be debilitating. It is frequently associated with anxiety. The diagnosis, that is unfortunately often belated, is a diagnosis of exclusion and relies on the anamnesis, various non specific signs, on the Nijmegens score and on a hyperventilation provocation test. A specialized treatment allows, in most cases, a good control of ventilation and the disappearance of symptoms.