Drawing on empirical evidence in medicine, economics, law, and anthropology, I argue that a market is uniquely capable of meeting the demand for transplantable kidneys, and that it may be arranged so as to operate safely. The welfare gains, expected to accrue to both vendors and recipients, are sufficient to justify sales. Having spelled out the considerations recommending a kidney market, I address the most forceful objections facing the proposal. Despite its currency, the claim that incentives will crowd out altruistic (...) donors and result in a decrease in supply is empirically unsupported and predicated on an implausible view of donorsâ motives. A host of objections claim vendorsâ will not give informed consent. Many such objections identify easily remediable problems, or impose unreasonable standards â standards that would rule out morally permissible kidney donation. And all presuppose a model of morally transformative consent that, I argue, is deficient. Two further challenges point to harms inflicted on those who do not participate in the market. Some claim that those in poverty will be subject to harmful social and legal pressure to vend. This objection fails to distinguish between being pressured to perform a specific act, and being under general economic pressure and having the option to perform an act. It, moreover, presupposes vending more common than is possible. Others worry that the market will give rise to unfair pecuniary externalities. This objection also presupposes that kidney sales will occur more often than is possible. But more importantly, the normative consideration that is supposed to make such externalities especially objectionable, in fact, recommends allowing sales. I also make a political case for kidney sales. I offer an account of the stateâs proper role in the market. I begin with a conception of democratic equality according to which the state is responsible to secure for its citizens the preconditions for democratic participation. I then show that this end would be promoted were the state to end the current prohibition on sales. (shrink)