Hereditary hemochromatosis is an autosomal recessive disorder that disrupts the body's regulation of iron. It is the most common genetic disease in whites. Men have a 24-fold increased rate of iron-overload disease compared with women. Persons who are homozygous for the HFE gene mutation C282Y comprise 85 to 90 percent of phenotypically affected persons. End-organ damage or clinical manifestations of hereditary hemochromatosis occur in approximately 10 percent of persons homozygous for C282Y. Symptoms of hereditary hemochromatosis are nonspecific and typically absent in the early stages. If present, symptoms may include weakness, lethargy, arthralgias, and impotence. Later manifestations include arthralgias, osteoporosis, cirrhosis, hepatocellular cancer, cardiomyopathy, dysrhythmia, diabetes mellitus, and hypogonadism. Diagnosis requires confirmation of increased serum ferritin levels and transferrin saturation, with or without symptoms. Subtyping is based on genotypic expression. Serum ferritin measurement is the most useful prognostic indicator of disease severity. Liver biopsy is performed to stage the degree of fibrosis with severe ferritin elevation or transaminitis, or to diagnose nonclassical hereditary hemochromatosis in patients with other genetic defects. Treatment of hereditary hemochromatosis requires phlebotomy, and the frequency is guided by serial measurements of serum ferritin levels and transferrin saturation. Iron avidity can result from overtreatment. If iron avidity is not suspected, it may mimic undertreatment with persistently elevated transferrin saturation. Dietary modification is generally unnecessary. Universal screening for hereditary hemochromatosis is not recommended, but testing should be performed in first-degree relatives of patients with classical HFE-related hemochromatosis, those with evidence of active liver disease, and patients with abnormal iron study results. Screening for hepatocellular carcinoma is reserved for those with hereditary hemochromatosis and cirrhosis.