BACKGROUND: Autoimmune hemolytic anemias are characterized by autoantibodies recognizing antigens on the Individual's own red blood cells, resulting in immune- mediated hemolysis. Blood transfusions have been regarded as hazardous in patients with autoimmune hemolytic anemia (AIHA) because of potential intensification of hemolysis and a presumed high incidence of alloimmunization. METHODS: We examined the pretransfusion and posttransfusion hemoglobin levels in 6 patients with autoantibodies in their sera, which showed panagglutinations with all bloods tested in the compatibility testing. They received 'least' incompatible blood because of inability to find compatible blood. RESULTS: When we compared pretransfusion hemoglobin level with posttransfusion hemoglobin level, in 5 of 6 patients with AIHA, the hemoglobin levels were increased after red cell transfusion. 4 patient who did not respond to transfusion therapy initially had an increase in hemoglobin level after steroid treatment. Any signs or symptoms indicating hemolytic transfusion reaction were not observed ducting the transfusion period in all patients. CONCLUSIONS: The decision to transfuse in AIHA should consider multiple factors including the patient's clinical status, the potential benefit of transfusion, the potential response to other therapeutic modalities, but must never be regarded as contraindicated, even though the compatibility test may be strongly incompatible.