The U.S. health care system is ostensibly market based and therefore at least partially reliant on competition and consumer demand to regulate costs. Yet information about an essential feature of market transactions—costs—is typically obscure to patients until long after treatment. When discussing what must be disclosed for informed consent, the same list of required information is often mentioned regardless of the health care system in question, and information about costs rarely merits a place within this list. However, our assumptions about (...) what a moral principle requires need to be responsive to the realities of the health care system in which the principle is applied.This paper explores the moral foundations of disclosure and informed consent to argue that, in a market‐based system of the sort found in the United States, these same considerations support a requirement to disclose out‐of‐pocket costs before patients receive care. Next, I consider two objections to this view: first, that health care practitioners should focus solely on medical considerations in their encounters with patients and, second, that disclosing out‐of‐pocket costs would be too difficult to be mandated. I argue that medical and financial interests are inseparable within the U.S. health care system. If the difficulties in disclosing costs are deemed insurmountable, then the current system may prove unsustainable, both morally and financially, since we face the same practical impediments to implementing any meaningful consumer‐driven, market‐based health care reform. Finally, I explore some of the consequences of failing to disclose costs. The requirements of disclosing costs can be supported by the principle of respect for autonomy, regardless of the consequences, but in light of the consequences of the decision of whether to disclose, a concern about justice provides further support. (shrink)