We describe the case of a 44-year-old woman with a delayed hemolytic transfusion reaction (DHTR). She had a history of two pregnancies and a blood transfusion, the details of which were unknown. At the time of her first vascular surgery on November 15, 1989, she received 1200 ml of crossmatch-compatible concentrated red blood cells (CRC). Before the first operation, screening for anti-RBC antibodies (Ab) was negative. At the time of the second admission on Feburary 15, 1996, anti-E Abs were detected by indirect antiglobulin test. She received 560 ml of E-antigen-negative, crossmatch-compatible, CRC for treatment of anemia on March 1 and 2, 1996. After this transfusion, total bilirubin (1.6 mg/dl) and lactate dehydrogenase (1355 IU/ml) were elevated on March 12, 1996. She had no evidence of clinical hemolysis. We suspected DHTR from these data, and therefore screened for anti-RBC Abs. Anti-E, Jka, Dia, Fyb, and S Abs were detected in blood samples obtained from the patient on March 12, 1996. Anti-E, Jka Dia, and S Abs were present more than 1 month and anti-Fyb Ab was disappeared at 18 days after transfusion.