The rising costs and inconsistent quality of health care in the United States have raised significant questions among professionals, policy makers, and the public about the way health services are being delivered. For the past 50 years, medical sociologists have made significant contributions in improving our understanding of the nature and impact of the organizations that constitute our health care system. In this article, we discuss three central findings in the sociology of health services: (1) health services in the U.S. are unequally distributed, contributing to health inequalities across status groups; (2) social institutions reproduce health care inequalities by constraining and enabling the actions of health service organizations, health care providers, and consumers; and (3) the structure and dynamics of health care organizations shape the quality, effectiveness, and outcomes of health services for different groups and communities. We conclude with a discussion of the policy implications of these findings for future health care reform efforts.