177 consecutive primary cadaveric renal transplantations were performed during April 1977-October 1980 in our centre. The graft survival in 58 recipients who were transfused with two units of blood for "immunological" reasons was the same as for 107 patients transfused with 1-96 units for medical reasons prior to transplantations. Twelve non-transfused patients had a significantly lower graft survival than the transfused ones (p less than 0.01). No additional beneficial effect of transfusions exceeding two in number was found. When three or more units of blood were given peroperatively to earlier transfused recipients, a lower early graft loss due to rejection was demonstrated than when two or less units were administered. The risk of sensitization of the recipient after two units of leucocyte poor blood was low.