This article is a review of the clinical and functional scores used for the assessment of the severity of asthma. Dyspnea is a key feature of asthma but its severity is difficult to interpret. Subjects with continuous airway obstruction may tend to be poor sensors of their dyspnea. The addition of other symptoms such as cough, wheezing, etc. to the dyspnea score can also be criticized. An international consensus conference recently proposed a clinical and functional scale to assess the severity of asthma. A combination of clinical, drug and functional information can best express the severity of asthma. Data originating from the authors work suggest that the correlations between clinical and drug scores on the one hand and peak expiratory flow rate values on the other hand are weak. It is the authors' final impression that the severity of asthma should be judged in a global way by considering various parameters.