There is continuing controversy over whether HLA matching should be a main factor in the allocation of kidneys from living unrelated donors. We report the correlation of HLA matching with graft survival in kidney transplantation recipients. Four hundred and one first kidney grafts from live donors with no blood relation to the recipients were analyzed. The transplantations were performed during the 10-year period from 1996 to 2005, in Baqyiatallah hospital, Tehran, Iran. HLA-A, -B, and -DR loci by PCR techniques, in both donor and recipient of a transplant, were typed. The transplants included in this analysis were ABO compatible. Three year graft survival rates were computed according to the method of Kaplan and Meier. From 401 subjects, 67%, and 32% of pairs showed 0-4, and 5-6 HLA-A-B-DR mismatches (MM), respectively. HLA antigen data showed that the number of 2-antigen mismatches for each locus was 31% for HLA-A, 39% for HLA-B, and 55% for HLA-DR. Three year graft survival was 83% and 56% for those recipients with 0-4, and 5-6 HLA-A-B-DR mismatches (MM), respectively (p>0.05). Three years graft survival was 82% and 50% for those recipients with 0 and 1-2 miss-matches in HLA-A (p>0.05), 73%, and 70% for those recipients with 0 and 1-2 miss-matches in HLA-B (p>0.05); 84% and 61% for those recipients with 0 and 1-2 miss-matches in HLA-DR (p>0.05). Despite the non-significant differences between the outcomes of groups with different numbers of mismatches, grafts with a lower number of miss-matches, tend to have a better survival, no matter what the type of allele is. More studies should address the potential impact of HLA mismatches on outcomes.