Graft and patient survival rates were analyzed in 239 consecutive first cadaver renal transplants as a function of time of administration of blood transfusion and the number of units given. There was no statistically significant difference in patient survival in comparing patients who were never transfused, patients not previously transfused who received blood peroperatively, those who received blood before transplantation only, and those who were transfused before transplantation and peroperatively. In fact, the best survival rates were achieved in patients who were not transfused previously. Graft survival rates were significantly better in the prior transfused groups compared to either the never transfused group or the larger no prior transfused group which included the peroperatively transfused patients. Graft survival of the peroperatively transfused patients was intermediate between the never transfused and the prior transfused patients. There was no statistically significant difference between graft survival rates of patients who received more than 6 units of blood with those receiving less than 6 units. Also, the time interval from the last transfusion to transplantation appeared to have no effect on graft survival. Since an intentional transfusion protocol carries the real risk of sensitization and delay or elimination of the transplantation option, a prospective study comparing peroperative with preoperative transfusions is suggested. Such a study would answer the questions of the risk of sensitization with prior transfusion and the value of peroperative transfusions.