Normoblasts were isolated from the blood of a patient with auto-immune hemolytic anemia in hemo-lytic crisis. These cells were agglutinable by type-specific sera and sera containing warm and cold hemagglutinins and by anti-globulin serum. It was thus demonstrated that agglutinogens make their appearance in the normoblastic stage of development. The possibility is suggested that this might lead to a direct antibody attack upon the bone marrow in immune forms of hemolytic anemia.