The UCLA Medical Center has initiated a "voucher program" under which a person who donated a kidney would receive a voucher that she could provide to someone of her choosing who could then use it to move to the top of the renal transplantation waiting list. If the use of such vouchers as incentives for donors is morally permissible, then cash payments for kidneys are also morally permissible. But, that argument faces five objections. First, there are some goods whose nature allows them to be exchanged for similar goods but renders them monetarily inalienable. Hence, kidneys might be exchanged for kidneys but not sold for cash. Second, voucher programs respect donor autonomy, whereas the offer of cash payments does not. Third, the burden of proof lies with the advocates of cash payments for kidneys to show that their benefits would outweigh the costs of their legalization. Fourth, allowing cash payments for kidneys would stifle medical innovation. Fifth, allowing cash payments for kidneys would result in these organs being used as collateral to secure loans-and that this would disadvantage potential borrowers who did not want to risk their kidneys in this way. This paper will rebut all these objections.