A 71-year-old woman showed a highly unusual pattern of iron distribution in the organism which was associated with iron overload. The hallmark of this disease was an extreme hypersiderinemia, the serum iron reaching about 800 μ g/l00 ml. There was a pigment cirrhosis of the liver, bronzed skin containing hemosiderin, and diabetes mellitus. Paradoxically, hemosiderin was not detectable in bone marrow macrophages, sideroblasts and erythrocytes were reduced, and there was a decrease in radioiron utilization of erythropoiesis, thus indicating insufficient iron supply. The pathogenesis of this disorder based on the formation of an autoantibody with specificity for transferrin thus producing a circulating immune complex which bound the majority of serum iron. Immunosuppression achieved a partial remission including a recovery of the patient’s general state, a rise in free transferrin, a decrease in serum iron, disappearance of hemosiderin in the liver, and a rise in erythrocyte production.