OECD countries face a challenge in responding to the demand for health workers over the next 20 years. This challenge arises in a world which is already characterised by significant international migration of health workers, both across OECD countries and between some developing countries and the OECD area. Whether these migration flows increase or decrease over the next 20 years is likely to depend largely on what combination of human-resource management policies and migration policies is adopted by OECD countries.