Because of the high percentage of national income and government budget typically associated with the provision of hospital services and because there is substantial evidence of hospital services could often be delivered more efficiently than they are, a number of OECD countries have increased the extent to which competitive mechanisms are adopted to increase the efficiency of hospital care delivery. Hospital services are complex set of products and services than comprise many different types of patient-oriented activities and not all services are equally subject to competition. For some services, such as emergency services, a hospital may have few if any competitors. For other services, such as inpatient scheduled surgeries, a hospital may compete for patients with other hospitals that offer comparable care. For still other services, such as diagnostic services, specialist consultations and outpatient services hospitals may at times compete with diagnostic centers, doctors’ offices and ambulatory surgery centers. Competition between providers of hospital services can have a number of impacts, including reducing excessive hospital stays, reducing costs of providing care and improving quality of care. Mechanisms for increasing competition or market forces identified in this paper include: collecting and distributing improved information on provider performance; supporting new entry when entry and exit costs are low; encouraging independent or private operation of facilities; improving allocation of human resources, particularly through reducing anticompetitive restrictions by professionals; introducing prospective pricing in combination with benchmarking; physician-led purchasing; providing for greater consumer choice, particularly when waiting lists are long; introducing contestable management of hospitals; and applying competition law in circumstances where public policy focuses on pro-competitive mechanisms. A competitive mechanism that might work in one system will not necessarily transfer well to another. Moreover, competitive mechanisms may at times increase costs. As health policy makers increase reliance on competitive mechanisms, they may need to think carefully about structural market conditions and potentially involve competition authorities when it appears that participants in the market are acting to restrain or eliminate competition.