A donor kidney exchange or cross-over program with exchange of organs between two donor-recipient pairs offers a possibility to realise living donor renal transplantation in cases of ABO-blood group incompatibility. The German transplantation law demands, in contrast to other countries, a close personal relationship between living donor and recipient. In this paper, we propose a concept based on the generation of a close personal relationship between donor-recipient pairs that allows cross-over renal donor transplantation considering the statement of the responsible medical-ethical institutions and the German transplantation law.