Public and private purchasers can shift the focus of the health care system from managing the delivery of medical services to improving health. We report on the efforts of the Pacific Business Group on Health to include health promotion and disease prevention in its definition of health care value, to pay health plans based on their performance in providing appropriate preventive care, and to encourage employers and workers to choose health plans that excel in promoting health. This example serves as a model for other purchasing groups by combining economic incentives and systems of accountability to achieve public health goals.