The PROMeTHEUS research project aims to address the scarcity of data and overall information on the mobility of health professionals in, to and from Europe. The project investigates the scale, relevance, and directions of health professional mobility, the reasons behind it, its possible implications, and the tools most adequate to respond to it. This project, funded under the European Commission’s 7th Framework Programme for Research, is led by the European Observatory on Health Systems and Policies.