ENROL, the European Rare Blood Disorders Platform has been conceived in the core of ERN-EuroBloodNet as an umbrella for both new and already existing registries on Rare Hematological Diseases (RHDs). ENROL aims at avoiding fragmentation of data by promoting the standards for patient registries' interoperability released by the EU RD platform. ENROL's principle is to maximize public benefit from data on RHDs opened up through the platform with the only restriction needed to guarantee patient rights and confidentiality, in agreement with EU regulations for cross-border sharing of personal data. Accordingly, ENROL will map the EU-level demographics, survival rates, diagnosis methods, genetic information, main clinical manifestations, and treatments in order to obtain epidemiological figures and identify trial cohorts for basic and clinical research. To this aim, ENROL will connect and facilitate the upgrading of existing RHD registries, while promoting the building of new ones when / where lacking. Target-driven actions will be carried out in collaboration with EURORDIS for educating patients and families about the benefits of enrolment in such registries, including different cultural and linguistic strategies. The standardized collection and monitoring of disease-specific healthcare outcomes through the ENROL user-friendly platform will determine how specialized care is delivered, where are the gaps in diagnosis, care, or treatment and where best to allocate financial, technical, or human resources. Moreover, it will allow for promoting research, especially for those issues that remain unanswered or sub-optimally addressed by the scientific community; furthermore, it will allow promoting clinical trials for new drugs. ENROL will enable the generation of evidence for better healthcare for RHD patients in the EU as the ultimate goal. ENROL officially started on 1st June 2020 with a duration of 36 months. ENROL is co-funded by the Health Programme of the European Union under the call for proposals HP-PJ-2019 on Rare disease registries for the European Reference Networks. GA number 947670