The National Asthma Education and Prevention Program (NAEPP), administered and coordinated by the National Heart, Lung, and Blood Institute, began developing a consensus set of science-based guidelines for diagnosis and management of asthma shortly after its establishment in 1989. With wide participation of asthma specialists from academia, research, and clinical care, as well as representatives from voluntary health organizations and federal agencies, the first Expert Panel Report: Guidelines for the Diagnosis and Management of Asthma was produced in 1991; a revision, the EPR-2, was published in 1997, and an update to the EPR-2 was published in 2002. The EPR-2 and EPR--Update 2002 comprise the prevailing science-based consensus concerning accurate information for health-care providers regarding asthma diagnosis and management. The EPR-2 has been disseminated nationwide and abstracted into a practical guide, a best practices pediatric guide, and a pocket guideline. However, although these asthma care principles have been widely endorsed, they have not been adequately applied. This report is a companion to the NAEPP Expert Panel Reports. It identifies a core set of 10 key clinical activities essential for ensuring that health care delivered to patients with asthma emphasizes the prevention aspect of care and addresses the components of care recommended in the Expert Panel Reports. The action steps listed for each key clinical activity suggest specific ways to accomplish the respective activity. The process of developing a core set of key clinical activities involved a detailed review of the EPR-2 guidelines and input from persons researching their implementation. These activities were identified in the context of the currently proposed asthma-specific measures for managed care, as well as the national health goals of Healthy People 2010 and the strategic plan of the U.S. Department of Health and Human Services (DHHS), Action Against Asthma. These reports complement each other to help health-care professionals, policymakers, patients, and the public work together to improve asthma care for the overall population and reduce asthma-related morbidity and mortality.