The present invention refers to a system and a method for the automatic detection of the expiratory flow limitation of a subject. In an embodiment thereof the system for the automatic detection of expiratory flow limitation of a subject comprises determining the respiratory impedance of the subject comprising an imaginary component and, eventually, of a real part or, at least, by applying a forcing signal with one or more spectral components to the airway opening of a subject combined with measuring time courses of pressure and flow at the airway opening determining at least one index linked to respiratory impedance or pressure and flow time courses indicating the positioning of at least one index in relation to a preset threshold value.