Few abnormalities have been described up to know in the red cell lineage of HIV patients except for a slight anemia. To better interpret this, a hemoglobin study was performed in a group of 71 HIV infected patients. By contrast to patients at stage II or III, those at stage IV of the disease had moderate elevation of HbA2 level. A second group of ten patients being at stage IV of HIV infection and having moderate increase in HbA2 level were found to have beta thalassemia-like unbalanced biosynthetic globin ratio, unlike a control group with chronic inflammation condition. The observed abnormality may be a feature reflecting the peculiar disordered erythropoiesis seen in the late stage of this disease.