Trauma registries are databases that document acute care delivered to patients hospitalised with injuries. They are designed to provide information that can be used to improve the efficiency and quality of trauma care. Indeed, the combination of trauma registry data at regional or national levels can produce very large databases that allow unprecedented opportunities for the evaluation of patient outcomes and inter-hospital comparisons. However, the creation and upkeep of trauma registries requires a substantial investment of money, time and effort, data quality is an important challenge and aggregated trauma data sets rarely represent a population-based sample of trauma. In addition, trauma hospitalisations are already routinely documented in administrative hospital discharge databases. The present review aims to provide evidence that trauma registry data can be used to improve the care dispensed to victims of injury in ways that could not be achieved with information from administrative databases alone. In addition, we will define the structure and purpose of contemporary trauma registries, acknowledge their limitations, and discuss possible ways to make them more useful.