This review discusses the historical aspects, current state of the art, and potential future advances in the areas of nomenclature and databases for congenital heart disease. Five areas will be reviewed: (1) common language = nomenclature, (2) mechanism of data collection (database or registry) with an established uniform core data set, (3) mechanism of evaluating case complexity, (4) mechanism to ensure and verify data completeness and accuracy, and (5) collaboration between medical subspecialties. During the 1990s, both the Society of Thoracic Surgeons (STS) and the European Association for Cardiothoracic Surgery (EACTS) created congenital heart surgery outcomes databases. Beginning in 1998, the EACTS and STS collaborated in the work of the International Congenital Heart Surgery Nomenclature and Database Project. By 2000, a common congenital heart surgery nomenclature, along with a common core minimal data set, were adopted by the EACTS and the STS and published in the Annals of Thoracic Surgery. In 2000, the International Nomenclature Committee for Pediatric and Congenital Heart Disease was established; this committee eventually evolved into the International Society for Nomenclature of Paediatric and Congenital Heart Disease (ISNPCHD). The working component of ISNPCHD is the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, also known as the Nomenclature Working Group (NWG). By 2005, the NWG cross-mapped the EACTS-STS nomenclature with the European Paediatric Cardiac Code of the Association for European Paediatric Cardiology and created the International Paediatric and Congenital Cardiac Code (IPCCC) ( http://www.IPCCC.NET ). This common nomenclature (IPCCC), and the common minimum database data set created by the International Congenital Heart Surgery Nomenclature and Database Project, are now utilized by both EACTS and STS; since 1998, this nomenclature and database have been used by both the STS and EACTS to analyze outcomes of more than 75,000 patients. Two major multi-institutional efforts have attempted to measure case complexity; the Risk Adjustment in Congenital Heart Surgery-1 and the Aristotle Complexity Score. Efforts to unify these two scoring systems are in their early stages but are encouraging. Collaborative efforts involving the EACTS and STS are under way to develop mechanisms to verify data completeness and accuracy. Further collaborative efforts are also ongoing between pediatric and congenital heart surgeons and other subspecialties, including pediatric cardiac anesthesiologists (via the Congenital Cardiac Anesthesia Society), pediatric cardiac intensivists (via the Pediatric Cardiac Intensive Care Society), and pediatric cardiologists (via the Joint Council on Congenital Heart Disease). Clearly, methods of congenital heart disease outcomes analysis continue to evolve, with continued advances in five areas: nomenclature, database, complexity adjustment, data verification, and subspecialty collaboration.