Abstract: Cancer registries provide insight into the burden of cancer by systematically recording data on new (pre)malignancies and/or in-situ tumours within a specific region, area, or treatment setting (e.g. hospital-based care). An understanding of the burden for a patient group at the population level is given by indicators such as incidence, survival, treatment modalities and timing, and prevalence. Mortality data are often obtained through national or regional death registries. Registries play a vital role in research into the causes of cancer, both by providing data on patterns and trends, and in different types of epidemiological studies (in particular, in their ability to follow up groups of persons exposed to a potential hazard). They comprise an essential element in the planning and monitoring of cancer control strategies as well as for identifying priorities in public health. Increasingly, registries in developed countries have begun to gather more data on treatments and outcomes (such as recurrences), which can be used for monitoring quality of care, guideline adherence, and outcome research.