The practical problems of setting up and operating a commercial inductively coupled plasma mass spectrometry (ICP-MS) instrument for routine analysis are discussed and the effect of choice of operating parameters on performance described. With the instrument used, a VG PlasmaQuad, the major parameter variables, plasma power and gas flows and the aperture-load coil spacing are normally kept constant for routine use. Under these conditions a sufficiently uniform response to a range of elements of different chemistries and atomic mass is obtained for the operator to use the instrument without repeated optimisation throughout the working day even though a variety of different sample types and matrices may be run. At fixed plasma power and spacing the only other critical parameter is the carrier gas flow-rate which is adequately stabilised in the instrument used by a precision mechanical flow regulator. The effect upon performance of variation of this flow-rate is shown for elemental response, doubly charged ion ratio and polyatomic ions and it is demonstrated that setting up for maximum elemental response minimises the effect of these interfering species. In practice carrier gas flow-rate is also normally fixed and setting up the instrument consists only of minor trimming of the ion-lens potentials for optimum response which is usually carried out when starting up for a day's running. Operated in this way the instrument is used for routine analysis by a variety of users on a wide range of matrices. An indication is given of the performance obtained under these conditions.