ABSTRACT This paper reviews the dynamics behind, and ethical issues associated with, the phenomenon of drug resistance. Drug resistance is an important ethical issue partly because of the severe consequences likely to result from the increase in drug resistant pathogens if more is not done to control them. Drug resistance is also an ethical issue because, rather than being a mere quirk of nature, the problem is largely a product of drug distribution. Drug resistance results from the over-consumption of antibiotics by the wealthy; and it, ironically, results from the under-consumption of antibiotics, usually by the poor or otherwise marginalized. In both kinds of cases the phenomenon of drug resistance illustrates why health (care) – at least in the context of infectious disease – should be treated as a (global) public good. The point is that drug resistance involves ‘externalities’ affecting third parties. When one patient develops a resistant strain of disease because of her over- or under-consumption of medication, this more dangerous malady poses increased risk to others. The propriety of free-market distribution of goods subject to externalities is famously dubious – given that the ‘efficiency’ rationale behind markets assumes an absence of externalities. Market failure in the context of drug resistance is partly revealed by the fact that no new classes of antibiotics have been developed since 1970. I conclude by arguing that the case of drug resistance reveals additional reasons – to those traditionally appealed to by bioethicists – for treating health care as something special when making policy decisions about its distribution.