Paediatric transplantation has dramatically changed the life expectancy of many children by providing treatment for organ failure who would otherwise have not survived. European Reference Networks (ERN) for rare diseases should serve as research and knowledge centres, updating and contributing to the latest scientific findings, treating patients from Member States and ensuring the availability of subsequent treatment facilities where necessary. ERN TransplantChild is focussed on both paediatric Solid Organ Transplantation (SOT) and Hematopoietic Stem Cell Transplantation (HSCT). Both SOT and HSCT are low-prevalence and complex conditions that require highly specialised expertise and resources. Current approaches are insufficient to fully address long-term graft and patient survival while providing the best possible QoL. The overall objective of the project is to create PETER, a new rational, efficient, interoperable, open, accessible paediatric transplant registry for all type of paediatric transplantation that allows generating real-world evidence monitoring by the identification of common outcomes for all types of transplant, and which can be used as a model to support care and research for the benefit of patients, improvement of the transplanted patient healthcare, their life expectancy and long-term quality of life of children and their families. Peter will lean on an interoperable technology platform with a module of business intelligence that will allow it to be a predictive registry directly impacting on the (a) process of patient care, improving the process of personalised clinical decision-making in the healthcare systems. PETER shall be built with the support and according to the standards set up by the European Platform on Rare Diseases Registration (EU RD Platform).