Difficult to control severe asthma is characterized by the persistence of inacceptable symptoms of asthma despite a continuous treatment with at least high doses of inhaled steroids and long acting bronchodilators. The diagnosis is done after a period of observation and some investigations that will allow confirm the diagnosis of asthma, eliminate alternative diagnosis and etiological forms that would be difficult to treat intrinsically (allergic broncho-pulmonary aspergillosis, Churg and Strauss disease, chronic eosinophilic pneumonia, occupational asthma). At the end of this period devoted to diagnosis a systematic approach is set up to take care of these patients. Therapeutic education includes action plans and measures for triggering factors avoidance in order to prevent exacerbations. Comorbidities such as rhinitis, nasal polyposis, gastro-oesophageal reflux and obesity are taken into account. Lastly, the treatment must be adapted according to the patient's preferences and aims, and to the asthma severity. Ultimately in steroid-dependent asthma, the lowest efficient dose is tracked continuously. For these patients, new molecules are needed.