In recent years, the number of proteins implicated in iron homeostasis has increased dramatically, and genetic causes have apparently been identified for the major disorders associated with tissue iron overload. These dramatic steps forward have transformed the way we look at iron-related disorders, particularly hemochromatosis. This review presents a concept of this disease that is based on this new knowledge and stems from the idea that, beyond their genetic diversities, all known hemochromatoses originate from the same metabolic error, the genetic disruption of human tendency for circulatory iron constancy. Hepcidin, the iron hormone, seems to hold a central pathogenic place in hemochromatosis, similar to insulin in diabetes: Genetically determined lack of hepcidin synthesis or activity may cause the disease.