The extant nomenclature for truncus arteriosus (TA) is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. A modified Van Praagh (VP) classification is proposed involving three main categories of TA: TA with confluent or near confluent pulmonary arteries (large aorta type, VP A1, A2), TA with absence of one pulmonary artery (VP A3), and TA with interrupted aortic arch or coarctation (large pulmonary artery type, VP A4). A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.