We analyzed the effect of blood transfusion (BT) on kidney allograft survival in 163 recipients. Transfused recipients (121) had better graft outcome than those never transfused (42), the difference being statistically significant at 3, 6, 12, and 24 months; however, the transfused group had a longer period of hemodialysis (P = 0.01). HLA antigen distribution does not bias the data. The group who had received the last BT within 3 months before grafting had a significantly better graft outcome than the nontransfused group (P less than 0.05 at 3, 6, and 24 months). They also did better (but not significantly) than the group who had been transfused more than 6 months before grafting. The group receiving two to five BTs had the highest rate of graft survival (P less than 0.05, 0.001, and 0.05 at 6, 12, and 24 months) as compared to the nontransfused. Practical suggestions for systematic BTs during hemodialysis are made.