The recent realization that hemochromatosis is a common condition has created opportunities to develop unified public health surveillance for this disorder and its complications and to design programs to prevent unnecessary illness and death resulting from this disorder. Public health surveillance for hemochromatosis can be used to measure the magnitude of the problem (for example, to establish the number of persons with evidence of early iron overload); identify research needs; reveal the natural history of the disease; detect changes in health care practices, such as use of screening tests; and evaluate interventions, such as phlebotomy. Existing surveillance has been limited to periodic measurement of morbidity and mortality done by using hospital discharge records, health examination surveys, vital statistics, and data from small research registries. The improvement of surveillance will entail the ongoing collection of information from population-based surveys, such as the Behavioral Risk Factor Surveillance System; the collection of data on provider practices (for example, through the National Ambulatory Medical Care Survey); and the establishment of population-based registries. Creating population-based registries requires consensus on case definitions; strategies to encourage case ascertainment and reporting; policies and procedures for protecting privacy and ensuring confidentiality; and partnerships among providers, researchers, and public health officials. Longitudinal data from population-based registries will provide insight into determinants of disease expression, such as pattern or degree of iron overload. This information is critical for developing evidence-based recommendations for population screening, monitoring changes in medical practices, and assessing the effect of preventive measures.