Over the past 50 years, technical advances have taken place in medicine that have greatly increased the possibilities of life-prolonging intervention. The increased possibilities of intervening have brought along new ethical questions. Not everything that is technically possible is appropriate in a specific case: not everything that could be done should be done. In the 1980s, a new term was coined to indicate a class of inappropriate interventions: “medically futile treatment”. A debate followed, with contributions from the USA and several western European countries. A similar debate later took place in Mediterranean countries, although with a different terminology. The purpose of this article is to provide an up-to-date and systematic analysis of the concept of futility, and to draw some conclusions on its operationalisation in medical practice. While the concept of “medical futility” in theory applies to all kinds of medical intervention that might be performed without being medically indicated—things such as certain medical screenings and cosmetic surgery—in practice the literature on “futility” deals only with life-saving and life-sustaining medical interventions. This article deals with this more limited application of the concept of “futility”.