Erythrocytosis, increased whole blood oxygen affinity, and iron overload were found in a 37-yr-old man. Electrophoretic techniques to demonstrate a hemoglobin variant showed no abnormality. Structural studies of the hemoglobin from this patient revealed an abnormal hemoglobin previously described as Hemoglobin Olympia, a high-affinity variant. Study of three generations in this family showed increased hepatic iron or iron absorption in some members of all three generations studied. The findings in this family are consistent with an increase in iron absorption due to the consequences of Hemoglobin Olympia and the heterozygous state for hemochromatosis (allele for hemochromatosis associated with HLA-A3, B7) or the presence in the family pedigree of three different alleles for hemochromatosis (alleles for hemochromatosis associated with HLA-A3, B7, HLA-A3, B15, and HLA-A9, B44) with the heterozygous state being manifest with increased iron absorption.