Objective To study the clinical effectives of red blood cell transfusion in patients with chronic aplastic anemia (CAA). Methods 425 CAA patients, from January 1995 to August 2007, were reviewed, and the rate of ineffective transfusions and its relationship to patients' age, sex, level of Hb before transfusion, times and volume of previous transfusions were analyzed.Results Of the 425 patients, ineffective transfusions occurred in 39 patients (9.2%). Of the 1 416 units of red blood cells transfused, 249 units (17.6%) were ineffective. The ineffective transfusions were not related to patients' age, sex or levels of Hb before transfusion, but were related to the times and volume of previous transfusions.Condusion In CAA patients, the more the times and the larger the volume of previous transfusions, the higher the rate of ineffective transfusion would occur.