Asthma is a chronic inflammatory airway disease that is commonly seen in the emergency department (ED). This article provides an evidence-based review of diagnosis and management of asthma. Early recognition of asthma exacerbations and initiation of treatment are essential. Treatment is dictated by the severity of the exacerbation. Treatment involves bronchodilators and corticosteroids. Other treatment modalities including magnesium, heliox, and noninvasive ventilator support are discussed. Safe disposition from the ED can be considered after stabilization of the exacerbation, response to treatment and attaining peak flow measures.