Disease management has shown great promise as a means of reorganizing chronic care and optimizing patient outcomes. Nevertheless, disease management programs are widely heterogeneous and lack a shared definition of disease management, which limits our ability to compare and evaluate different programs. To address this problem, the American Heart Association's Disease Management Taxonomy Writing Group developed a system of classification that can be used both to categorize and compare disease management programs and to inform efforts to identify specific factors associated with effectiveness. The AHA Writing Group began with a conceptual model of disease management and its components and subsequently validated this model over a wide range of disease management programs. A systematic MEDLINE search was performed on the terms heart failure, diabetes, and depression, together with disease management, case management, and care management. The search encompassed articles published in English between 1987 and 2005. We then selected studies that incorporated (1) interventions designed to improve outcomes and/or reduce medical resource utilization in patients with heart failure, diabetes, or depression and (2) clearly defined protocols with at least 2 prespecified components traditionally associated with disease management. We analyzed the study protocols and used qualitative research methods to develop a disease management taxonomy with our conceptual model as the organizing framework. The final taxonomy includes the following 8 domains: (1) Patient population is characterized by risk status, demographic profile, and level of comorbidity. (2) Intervention recipient describes the primary targets of disease management intervention and includes patients and caregivers, physicians and allied healthcare providers, and healthcare delivery systems. (3) Intervention content delineates individual components, such as patient education, medication management, peer support, or some form of postacute care, that are included in disease management. (4) Delivery personnel describes the network of healthcare providers involved in the delivery of disease management interventions, including nurses, case managers, physicians, pharmacists, case workers, dietitians, physical therapists, psychologists, and information systems specialists. (5) Method of communication identifies a broad range of disease management delivery systems that may include in-person visitation, audiovisual information packets, and some form of electronic or telecommunication technology. (6) Intensity and complexity distinguish between the frequency and duration of exposure, as well as the mix of program components, with respect to the target for disease management. (7) Environment defines the context in which disease management interventions are typically delivered and includes inpatient or hospital-affiliated outpatient programs, community or home-based programs, or some combination of these factors. (8) Clinical outcomes include traditional, frequently assessed primary and secondary outcomes, as well as patient-centered measures, such as adherence to medication, self-management, and caregiver burden. This statement presents a taxonomy for disease management that describes critical program attributes and allows for comparisons across interventions. Routine application of the taxonomy may facilitate better comparisons of structure, process, and outcome measures across a range of disease management programs and should promote uniformity in the design and conduct of studies that seek to validate disease management strategies.