The case of a 58-year-old male with severe anemia after hemicolectomy is described. The patient proved to be Kp(b-), and the serum contained anti-Kpb. Because no Kp(b-) donors were available, two incompatible units are administered after intravenous gammaglobulin (400 mg/kg/day) and hydrocortisone (500 mg). The tolerance was good, without signs of increased red cell destruction. Pending the arrival of compatible blood from the American Red Cross, the hematocrit reached 18%, and the direct antiglobulin test remained negative.