OBJECTIVE Cromer system antigens, a series of blood group antigens of very high frequency, are not considered to be clinically significant in transfusion. In renal transplantation only the ABO blood group antigens are considered essential. The Drori blood group antigen is present in serum and has been found to reside on the renal tubular basement membrane and Bowman's capsule. The effect of anti-Dra on the renal parenchyma has not been evaluated. METHODS A unique case of renal transplantation of an incompatible Dr(a+) kidney to a Dr(a-) patient with anti-Dra in her serum is presented. RESULTS Graft function was immediately good. The titer of anti-Dra remained unchanged following transplantation. CONCLUSIONS The successful outcome of a case of a Drori (Dra)-incompatible kidney transplantation confirmed the lack of clinical significance of the anti-Dra relating to transplantation.