Transplantations using grafts from living donors were performed on 70 patients with chronic kidney failure, 66 of them involved matching recipients-donors and four involved non-matching recipients-donors. Immunological data were analyzed in 56 pairs of recipients and patients. Of these pairs, one was identical, seven had three identical antigens, 46 were haploidentical at A and B loci, one pair was identical in one antigen and one pair was completely incompatible. The survival of transplanted kidneys largely depended on the degree of histocompatibility. In 33 (59%) transplantations kidneys are functioning from more than 36 months. In the group of seven transplanted pairs with three identical antigens kidneys are functioning in six cases, with four of them functioning from more than 72 months. In the remaining patients (41 patients [73%]) kidneys are functioning, with 8 of them functioning from more than 10 years. The existence of HLA antibodies was investigated. Preimmunization was found in 18 (32%) patients and correlated with the number of blood transfusions. Rejection crises were observed in 12 (21%) patients. As the number of blood transfusions per patient increased the number of rejection crises decreased. Rejection crises were also observed in haploidentical pairs, with a relative risk > 30%. They occurred in the first 2 weeks following transplantation.