The significant worldwide increase in asthma-related severity and mortality has evoked increasing concern from the medical community. To enhance early recognition and appropriate therapeutic intervention of asthma, the National Heart, Lung, and Blood Institute's National Asthma Education Program convened an expert panel to develop guidelines for the diagnosis and treatment of asthma. The guidelines discussed in this article emphasize that airway inflammation is a central characteristic of asthma. Appropriate therapy must include four components: the use of objective measures of lung function to assess the severity of asthma and to monitor the course of therapy, comprehensive pharmacologic therapy that includes medications to reverse and prevent the underlying airway inflammation and to relieve the bronchoconstriction, environmental control measures to avoid or control factors that precipitate asthma exacerbations, and patient education to foster a partnership among the patient, the patient's family, and the clinician.