We retrospectively examined the effect of HLA-DRB1 matching at the DNA level compared with serological HLA-DR matching on acute rejection and graft survival in patients who underwent primary cadaveric renal transplantation. For patients with serological HLA-DR zero mismatch, the incidence of acute rejection in patients with zero DRB1 mismatch (3/20; 15%) was significantly lower than in those with one or two DRB1 mismatches (10/21; 48%). Five-year graft survival in patients with zero DRB1 mismatch was 100%, whereas that in those with one or two DRB1 mismatches was 76%, although the difference was not statistically significant. The fact that HLA-DRB1 matching at the DNA level influenced incidence of graft rejection after cadaveric renal transplantation is analogous to results in living-related renal transplantation. It is suggested that avoidance of mismatching for DRB1 alleles at the DNA level in recipient selection of cadaveric renal transplantation leads to an improvement of graft outcome.