The shortage of kidneys from brain-dead donors for transplantation has made it necessary to look for alternatives. Living kidney donation is one possibility. However, because of ABO blood group incompatibility or immunological reasons, transplantation of kidneys from a living donor is not always possible. The seven Dutch kidney transplantation centers have developed a joint protocol for crossover, or paired donor exchange, kidney transplantation. To ensure a fair chance for all participating donor-recipient pairs, the Dutch Transplantation Foundation has developed an allocation algorithm to match compatible donor-recipient pairs. A crossover match is performed every 3 months. The computer program developed by the Dutch Transplantation Foundation to match compatible donor-recipient pairs calculates the match probability (MP) of every potential recipient. The MP takes into account the peak panel-reactive antibodies (%PRA) of the recipient, the incidence within the crossover donor population of (compatible) ABO blood group, and HLA unacceptables of the recipient. The potential recipient with the lowest MP, in other words, the recipient with the smallest chance of finding a compatible donor in the pool, is ranked first. Until now, three matches have been performed in the Netherlands. A total of 53 pairs from all seven Dutch transplantation centers have participated. For 22 of the pairs a compatible donor-recipient pair was found.