The U.S. chronic illness burden is increasing and is felt more strongly in minority and low-income populations: in 2005, 133 million Americans had at least one chronic condition. Prevention and management of chronic disease are best performed by multidisciplinary teams in primary care and public health. However, the future health care workforce is not projected to include an appropriate mix of personnel capable of staffing such teams. To prepare for the growing chronic disease burden, a larger interdisciplinary primary care workforce is needed, and payment for primary care should reward practices that incorporate multidisciplinary teams. [Health Affairs 28, no. 1 (2009): 64-74; 10.1377/hlthaff .28.1.64] I n 2 0 0 5 , 13 3 m i ll i o n a m e r i c an s w e r e l i v i n g with at least one chronic condition. In 2020, this number is expected to grow to 157 million. In 2005, sixty-three million people had multiple chronic illnesses, and that number will reach eighty-one million in 2020. 1 Not surprisingly, the proportion of the population diagnosed with chronic conditions increases with age (Exhibit 1). More worrisome is the striking gap between the high prevalence of chronic conditions among people who are below the federal poverty level compared with the average prevalence in the general population. The cost burden of chronic illness-currently 78 percent of total health spending-will increase markedly by 2023 (Exhibit 2). The number of people with diabetes is expected to double in the next twenty-five years, from twentyfour million to forty-eight million. By 2023, the number of people with chronic mental disorders may increase from thirty million to forty-seven million. Similar increases are forecast for virtually every common chronic condition. 6 4 J a n u a r y / F e b r u a r y 2 0 0 9 R e o r g a n i z i n g C a r e n Reasons for increased prevalence. Reasons for the increased prevalence of chronic conditions are multifactorial-including an aging population plus a rise in disease-specific risk factors such as obesity. A comparison of chronic disease prevalence in the United States and in ten European countries reveals a markedly lower prevalence in Europe of heart disease, hypertension, diabetes, obesity, and arthritis. This difference may be attributable to a healthier diet and lower poverty rates in Eu- 4 The population over age eighty-five, the group with the highest proportion of people with multiple chronic conditions, is projected to grow from five million in 2005 to twenty-one million in 2050, ensuring a major increase in the number of very-high-cost patients.n Four policy questions. These data raise both general societal issues and specific policy questions. In this paper we address four specific policy questions, with greatest emphasis placed on questions 2 and 3: (1) Can dramatic public health prevention slow down the rate of increase of chronic disease prevalence? (2) Should chronic care be delivered chiefly by specialist physicians, generalist physicians, or multidisciplinary teams...