The aim of this study was to evaluate possible associations between endothelium-dependent vasodilatation (EDV) and cardiovascular structure and function. EDV could influence peripheral resistance and be affected by atherosclerosis and might thereby influence indices of cardiovascular structure and function. In a group of 31 apparently healthy men and 25 women (age range 20-69 years), EDV was evaluated by infusion of metacholine (4 micrograms min-1), and endothelium-independent vasodilatation (EIDV) was assessed by nitroprusside infusion (SNP, 10 micrograms min-1) in the brachial artery. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Left ventricular (LV) geometry and function and the intima-media thickness in the carotid artery were assessed by ultrasonography. The stroke index to pulse pressure ratio was used to evaluate arterial compliance. Several indices of cardiovascular structure and function were found to be related to an index of endothelial function, the EDV to EIDV ratio. Furthermore, left ventricular mass (LVM), the atrio-ventricular plane displacement, E/A ratio, IVRT, the intima-media thickness of the carotid artery and arterial compliance were all significantly related to both EDV and EIDV in women. However, most indices of cardiovascular structure and function, as well as endothelial function, change with age and only the relation between LV diastolic function and endothelial function in men remained significant (P < 0.05) after including age in multiple regression analysis. Age was related to both cardiovascular structure and function, as well as to endothelial function. Multiple regression analysis showed that ageing generally affects cardiovascular characteristics and endothelial function in parallel in these healthy subjects.