In the context of the Community Programme in the field of Health, the European Commission financed a series of initiatives to support the development and use of indicators for planning health services for Rare Diseases (RDs). The European Project for Rare Disease National Plans Development (EUROPLAN) elaborated a set of 59 process and outcome indicators, for monitoring the implementation and for evaluating the impact of the National Plans on RDs. Due to the high number and difficulty in handling the indicators, the subsequent Joint Action "Working for RDs" planned to derive a selection of 21 core indicators that were adopted by the European Union Committee of Experts on RDs in June 2013. The descriptive study carried out in the framework of the Joint Action to select the key indicators to orient policies for RDs shows that core indicators represent an excellent opportunity to share knowledge and comparability among Member States