The stethoscope, and its use in the medical examination, has become iconic of ‘doctors’ and their work. Drawing on fieldwork in a London hospital, this article explores why this is so. It argues that the application of this instrument in a clinical situation allows for a particularly neat enactment of key ‘dispositions’ of what might be described as a doctor ‘habitus’ (Bourdieu, The Logic of Practice, 1980). Examining the politics of stethoscope ownership and display, the article also reveals some of the capacities or types of ‘agency’ doctors assign to the instrument that they exploit in the day-to-day production and performance of their medical identity (Gell, Art and Agency in Anthropological Theory, 1998). At a time when new diagnostic technologies threaten to render the stethoscope obsolete, doctors are shown to want to retain the instrument as a symbol of the skill and knowledge they possess, but which they believe to be increasingly devalued and undermined in modern medicine.