The burden of chronic diseases is tremendous, and traditional methods of healthcare delivery are unsuitable for addressing these needs. Chronic disease management has emerged as a new strategy for chronic disease care, but a consistent definition has not been utilized. Our objective is to present an operational definition of chronic disease management. Based on prior systematic reviews of chronic disease management programs, we propose a definition encompassing the main constructs noted in our reviews.We define chronic disease management in the clinical setting as an organized, proactive, multi-component, patient-centered approach to healthcare delivery that involves all members of a defined population who have a specific disease entity (or a subpopulation with specific risk factors). Care is focused on, and integrated across the entire spectrum of the disease and its complications, the prevention of comorbid conditions, and relevant aspects of the delivery system. Essential components include identification of the population, implementation of clinical practice guidelines or other decision-making tools, implementation of additional patient-, provider-, or healthcare system-focused interventions, the use of clinical information systems, and the measurement and management of outcomes.Consistent use of this definition and adequate documentation of the component interventions of chronic disease management will enable comparisons among programs and outcomes in evaluation research and clinical practice. Most importantly, it will assist in determining which specific interventions or combinations thereof, implemented as part of chronic disease management, are most effective.