A 70 year old Black woman had chronic hemolytic anemia without recurrent painful crises. Hemoglobin pattern by electrophoresis was hemoglobin S (69 to 71 per cent), hemoglobin A 2 (4.6 per cent) and hemoglobin F (24 to 27 per cent). No hemoglobin A was detected, and the hemoglobin F was distributed heterogeneously in the red cells. Reticulocyte alpha/nonalpha globin chain synthetic ratios were 1.44 to 1.62. Thus, the patient had a high hemoglobin F variant of S-beta zero ( β 0) thalassemia which has not been described previously. Her clinical course has been mild in comparison with S- β 0 thalassemia patients who do not have extremely elevated hemoglobin F levels.