A case of blood transfusion reactions due to anti-E (rh'') antibody is reported. The patient was a 41-years old married woman, nullipara, and was admitted to the hospital because of chronic anemia due to blood loss (myoma uteri cum hypermenorrhea). Her blood type was A, M, Q, CDe/cde (R1/r), and that of her husband was A, N, q, CDe/cde. After two blood transfusions, 100 ml each, with A, …E, … blood types, the patient deve-loped high fever and hemoglobinuria when she was transfused with A, …E, … blood, but not with A, …e… blood. Direct and indirect Coomb's test was positive after transfusion reaction and the presence of anti-E antibody was confirmed both by us and by Dr. Levine of the Ortho Research Foundation of the U.S.A..