It has been proposed that the liver protects a simultaneously transplanted kidney from acute rejection. Using the United Network for Organ Sharing database, we compared the kidney allograft data from 248 combined liver and kidney transplants (LKT) with a control group comprising 206 contralateral kidney alone transplants (KAT) from the same donor. The LKT and KAT groups were identical with respect to most baseline parameters, save a greater degree of HLA matching in the KAT group. The overall 3-year graft survival rate was higher in the KAT group compared with the LKT group (80% vs 68%, P < 0.01). When these data were censored to remove death as a cause of graft loss and to minimize the matching effect, the 3-year survival rates were not statistically different (78% for KAT and 81% for LKT, P = NS). We conclude that the liver neither protects the kidney from rejection nor improves kidney allograft function or survival after LKT.