Injuries have emerged as the leading cause of child and adolescent morbidity and mortality in developed countries. Efforts to control injuries require injury surveillance and research, creating the need for standard variable definitions and categorizations. Advantages of such standardization include increased comparability of data sets, avoidance of spurious conclusions based on idiosyncratic definitions and categories and the potential to combine data sets (e.g. on injuries and population counts) to yield new information. Pertinent standards will differ depending on the purposes for which the data are collected. More limited (core) data are appropriate to surveillance and more extensive data to research. Existing standards that are likely to be most useful to pediatric injury investigators are the International Classification of Diseases External Cause (E) codes (which provide mechanism-of-injury diagnoses and are the international gold standard for injury data reporting) and the Standard Definitions for Childhood Injury Research recently released by the United States National Institute for Child Health and Human Development, which include both core and complete variable listings. Some key core definitions from the latter report are presented.