Policy makers in several industrial countries are seeking to limit the rise in health care cost growth by supporting coordinated or integrated care programs, which differ from most prevailing forms of medical organization in how physicians are paid and how they work in groups. However, as long as fee-for-service payment systems remain an option, general practitioners will be reluctant to embrace coordinated care because it would give them less autonomy in how they practice. A study in Switzerland indicates that general practitioners will require a pay increase of up to 40 percent before they are willing to accept coordinated care, and a similar study found that Swiss consumers wanted a substantial reduction in premiums to accept it. These findings suggest that provisions of US health care reform designed to encourage the growth of coordinated care-such as accountable care organizations and medical homes-may face a challenging future.