The haemodynamic effects of anaesthetic induction with i.v. etomidate have been assessed in 36 patients. The variables studied were recorded under basal conditions and 3 and 10 min after induction, before surgical stimulus. There was a reduction in cardiac output, stroke volume and arterial pressure, and a compensating increase in heart rate. Pulmonary arterial pressure and vascular resistance, central venous pressure and pulmonary capillary wedge pressure were virtually unchanged. Although etomidate has a negative inotropic effect, the variables which were depressed remained at all times within acceptable limits.