An innovative program recently initiated at the University of California, Los Angeles (UCLA) Medical Center allows people to donate a kidney in exchange for a voucher that a loved one can redeem for a kidney if and when needed. As a relatively new practice, the ethical implications of advanced kidney donation have not yet been widely discussed. This paper reflects on some of the bioethical issues at stake in this new donation program, as well as some broader philosophical issues related to the meaning and moral salience of commodification. I first consider whether the literature on commercial markets in organs--a longstanding topic of bioethical debate--can meaningfully inform ethical analysis of kidney voucher programs. Specifically, I consider whether and to what extent common objections to the exchange of kidneys for cash also apply to the exchange of kidneys for "kidney vouchers." Second, I argue that the contrast between the ethical issues raised by these two practices highlights the need to understand commodification as existing on a continuum, with different degrees of commodification giving rise to different ethical issues. Doing so can help sharpen our understanding of commodification as a moral concept, as well as its relevance to broader debates about the moral limits of markets.