Ninety-two families with familial hemochromatosis were reviewed and analyzed in regard to hepatic iron and the value of the hepatic iron index (hepatic iron/age). Hepatic iron was measured in 29 hemochromatosis homozygotes, in 10 hemochromatosis heterozygotes, and in 30 control patients with other liver diseases. Hepatic iron content increased with age in homozygotes. Hepatic iron index differentiated homozygotes from heterozygotes (P less than 0.05) and heterozygotes from controls (P less than 0.05). The hepatic iron index is a useful measurement in the diagnosis and management of patients with familial hemochromatosis.