Abstract: The surface of a diaphragm 26 is maintained in hygienic condition during examination of successive patients by positioning a clean or sterile diaphragm cover 10 over the diaphragm during examination. The cover 10 can be disposed or resterilized for further use. The cover 10 includes a flexible, resilient, imperforate membrane sheet 32 mounted on a rigid rim member 30 containing at least one, and preferably two, tabs 34 which clip over the outer edge of the ring 26. The rim of the cover is designed to have a loose sliding fit over the cup and the cover sheet is very thin and deformable so that there is no interference with sound collection and transmission.