Medical criteria rooted in evidence-based medicine are often seen as a value-neutral ‘trump card’ which puts paid to any further debate about setting priorities for treatment. On this argument, doctors should stop providing treatment at the point when it becomes medically futile, and that is also the threshold at which the health purchaser should stop purchasing. This paper offers three kinds of ethical criteria as a counterweight to analysis based solely on medical criteria. The first set of arguments concerns futility, (...) probability and utility; the second, justice and fairness; the third, consent and competence. The argument is illustrated by two recent case studies about futility and priority-setting: the US example of ‘Baby Ryan’ and the UK case of ‘Child B’. (shrink)