BackgroundAlthough several National Data Registries for Congenital Heart Disease (CHD) exist, few are comprehensive and contemporary. A National Australian CHD Registry has been developed that aims to redress this by creating the first comprehensive data collection for CHD children and adults, initially across Australia. MethodsWe defined and collected a minimum dataset of demographics, diagnoses, and procedures from people with CHD presenting at participating quaternary CHD services Australia-wide. Data were collected from a range of clinical data sources. Diagnoses and procedures were standardised to the European Paediatric Congenital Code – Short List. Methodological limitations were carefully documented. ResultsFrom 8 participating institutions, an initial 359,084 patient records were assessed for eligibility and 68,234 unique individuals with structural CHD have been included in the current dataset. There were 25,157 (37%) people with mild CHD, 25,157 (37%) with moderate CHD, and 13,530 (20%) with severe CHD (6% unknown complexity). The most common diagnoses were Ventricular Septal Defect (16,781, 25%), Atrial Septal Defect (6,607, 10%), Aortic Valve Disorders (5,516 8%), Coarctation of the Aorta (5,321, 8%), Tetralogy of Fallot (4,489, 7%), Transposition of the Great Arteries (4,009, 6%). ConclusionThe data presented here represents the most comprehensive cohort collected for the Australian CHD population thus far and is comparable with the largest contemporary CHD registries around the world. This Registry represents a key resource for improved understanding of the CHD population and will drive better care and outcomes for people living with CHD.