This report contains the first-ever comparative analysis of the role and performance of private health insurance in OECD countries. Issues discussed include: private health insurance markets and policy issues arising from their interdependence with publicly financed health coverage schemes; the impact of private health insurance against health policy objectives; strengths and challenges of private health insurance in relation to health system performance; and how governments can help ensure that private health insurance markets make a positive contribution to the performance of health systems. It includes examples of useful practices for developing more efficient and equitable health insurance markets.