Purchaser-provider systems in health care are being implemented in several countries and are under consideration in many more. These new arrangements are described for the United Kingdom, Finland, New Zealand, and Australia, and in each case responsibility for funding, purchasing, providing, and ownership is identified. The four systems, along with managed care organisations in the United States, are also compared with regard to several important features. There is a fundamental similarity between these purchaser-provider arrangements but several key differences are well worth systematic study. This is a major challenge for academic bodies in Britain and other countries, and the opportunity to learn from each other should not be missed.