Asthma is one of the most common diseases in developed nations. A pathognomonic feature of asthma is episodic aggravations of the disease; these exacerbations can be life-threatening and contribute to a significant proportion of the public health burden of asthma. In the emergency department, successful management of asthma exacerbations requires early recognition and intervention before they become severe and potentially fatal. This review summarizes the pathophysiology, stabilization and assessment, diagnosis and treatment, and disposition and outcomes for asthma. Figures show the management of asthma exacerbations in the emergency department and hospital, pooled odds ratio comparing inhaled corticosteroids and oral corticosteroids with oral corticosteroids alone following emergency department discharge, and an asthma discharge plan at the emergency department. Tables list current asthma prevalence among selected demographic groups in the United States, risk factors for fatal asthma exacerbations, differential diagnosis of asthma exacerbations, and dosages of drugs for asthma exacerbations. This review contains 3 figures, 16 tables, and 88 references. Key Words: Asthma, allergic bronchopulmonary aspergillosis, gastroesophageal reflux disease, sinus disease, breathlessness, shortness of breath