Cadaver donor graft survival data obtained between 1970 and 1980 show that transfused patients had statistically significant improvements in transplant survival rates for each of the 11 years, as compared with untransfused patients. Patients with many transfusions could be successfully grafted at any time following their last transfusion, whereas those with few transfusions had varying success rates at different intervals following their last transfusion. Even one transfusion produced a statistically significant improvement (52 +/- 3% one-year graft survival) as compared with no transfusion (41 +/- 1%) and survival rates increased up to 14 transfusions (75 +/- 7%). Subsequent transfusions did not appear to be more beneficial, although there is a possibility that patients who receive a larger number of transfusions are medically different from those who receive fewer transfusions. Most important, patients who had cytotoxic antibodies following transfusions had a higher transplant survival rate than did untransfused patients with no antibodies. Thus cytotoxic antibodies per se are not harmful to transplants. Patients with cytotoxins are not automatically at a higher risk and are not "sensitized" in the conventional sense. They are only unable to accept grafts from certain donors.