Septicemia is a rare complication of blood transfusion. This is probably primarily due to the use of sealed disposable containers for blood collection and the storage of red cell-containing components at 4 degrees C. However, despite these measures, septicemia due to blood transfusion continues to occur. We report here a fatal case of Yersinia enterocolitica septicemia due to a contaminated unit of red cells which was collected from an apparently healthy, asymptomatic blood donor. The organism grows at cold temperature and multiplies during storage of red blood cell-containing components. Contaminated components do not show any visible abnormalities. The possibility of transfusion-transmitted Y. enterocolitica should be considered in patients who have symptoms of sepsis or shock following transfusion.