Endo-ERN covers an exceptionally large number of rare conditions across the age span. Whilst some conditions are covered in established international disease registries, there are several that are not. Collectively, the existing detailed disease registries display a number of qualities associated with good registry practice but the involvement of patients, participation by members of Endo-ERN and the research output of these registries is variable with a minimal capacity for interoperability. The central cause that has led to this variation is the lack of a core endocrine registry and the lack of core standards for registries. The overall objective of the European Registries for Rare Endocrine Conditions (EuRRECa) is to ensure that Endo-ERN acheives its mission of driving up standards of clinical care and patient-centred research through maximizing participation in disease registries. The project will do this by developing a new core endocrine registry that collects a core dataset that also includes objective markers of clinical outcome, runs an e-surveillance programme and signposts participants to high-quality, detailed, disease-specific and patient-centred registries that have been evaluated by EuRRECa. The project will achieve the above objective by building on the structure that has been created by Endo-ERN. EuRRECa will receive guidance from expert advisory groups that align with the thematic groups of Endo-ERN. Their guidance will flow through work packages that will review the needs of patients, parents and ethics, evaluate the quality and interoperability of datasets and combine them wth patient centred clinical outcomes. Clear policies that are acceptable to patients, researchers and industry for accessing data for research coupled with widespread dissemination and knowledge-exchange through closely affiliated professional endocrine societies, patient support groups and across all the ERNs will ensure that EuRRECa is sustained over the longer term.