A 59-year-old woman with metastatic colon cancer, immunosuppressed secondary to chemotherapy and prolonged granulocytopenia, developed acute Chagas' disease that was fatal. During her illness, she received transfusions with large numbers of blood components. Although we were unable to identify an infected donor, we believe her infection was acquired from transfusion of a contaminated blood component. Recently, three similar cases were reported in North America. An influx of immigrants from areas in which Chagas' disease is endemic may account for the increased number of cases of transfusion-associated Chagas' disease in this country.