Asthma is an inflammatory disorder of the airway associated with airflow obstruction and bronchial hyperresponsiveness that varies in severity across the spectrum of the disease. Asthma affects 5-7% of the population of North America and Europe, and the prevalence is increasing. Most patients with asthma are easily diagnosed, responding to standard treatment with a short-acting inhaled beta2-agonists for symptom control, and to long-term therapy to including inhaled glucocorticosteroids to control airway inflammation. However a subgroup of patients with asthma (likely approximately 10%) have more troublesome disease reflected by high medication requirements to maintain good disease control or persistent symptoms, asthma exacerbations, or airflow obstruction despite high medication use. A term to describe this subgroup of asthmatic patients is "Refractory Asthma". Patients with difficult to control asthma require a rigorous and systematic approach to their diagnosis and treatment. It is critical to make a diagnosis of asthma and to exclude other airways diseases and to identify whether there are any correctable factors that may contribute to their poor control. Another poor adherence to therapy is common reason for a poor response. Treatment involves optimizing corticosteroid inhaled therapy, assesing additional controllers, such as inhaled beta2-agonist, leukotriene inhibitors, anti-immunoglobulins (Ig), oral corticosteroids and sustained-release theophylline.