We examined the iron status of 23 adult patients with hemoglobin H (Hb H) disease. None of them had received multiple blood transfusions or prolonged iron therapy. Studies included serum iron and ferritin concentrations, transferrin saturation, a desferrioxamine test, computed tomography (CT) scan of the liver, and liver biopsy. Iron overload was found in 17 patients (73.9%), especially in males and in patients with splenomegaly (92.9% and 100%, respectively). Four patients with excessive alcohol consumption had clinical manifestations of severe iron overload. Idiopathic hemochromatosis associated HLA antigens, i.e., HLA-A3, -B7, or -B14, were not found in any of the 15 patients tested. These findings indicate that iron overload is common in adult patients with Hb H disease; such patients should abstain from alcohol and be considered for treatment with an iron chelating agent before irreversible organ damage occurs.