Roughly 40% of asthmatics are or have been smokers. These smoking asthmatics have been largely overlooked in the past. Tobacco is today considered as a risk factor for asthma and it seems that smoking asthmatics exhibit a different phenotype as compared to non smoking asthmatics. The inflammatory substrate differs widely, not only with respect to the type of cells present in the airways, but also with respect to the mediators brought into play. On the clinical point of view the asthma of smokers is also more severe that in non smokers, both at the symptomatic and the functional level. The asthma severity in smokers is partly linked to a resistance to inhaled corticoids, the cornerstone of maintenance treatment in asthma. This makes urgent to assess alternative treatment to inhaled corticoids for this asthma phenotype, but also emphasizes the need to support smoking cessation in asthmatics.