Health Services Research is the systematic investigation and evaluation of the health services with respect to their availability, accessibility, coverage, effectiveness, efficiency, utilization and costs. Although some important developments like the introduction of national health insurance or the creation of a national health service led in given European countries to limited efforts in Health Services Research it has only been recently that the need for such research has become recognized. The cost explosion in health care and growing doubts about the effectiveness of given health care interventions provide leverage for a greater effort in Health Services Research. The World Health Organization created in 1977 the European Advisory Committee for Medical Research and Health Services Research. This Committee has identified five priority areas for research: 1. standardization of methods, measurements and terminology in biomedical and health services research 2. prevention, prophylaxis and early detection 3. evaluation of drugs and other therapeutic and diagnostic substances 4. problems in health care delivery 5. economic aspects of health care Adressing these problems will call at the national level for the development of a critical mass of capable health services researchers. It will also require substantial financial resources.