Clinical trials have demonstrated that treatment of hypercholesterolemia with HMG-CoA reductase inhibitors (statins) is beneficial in primary and secondary prevention of vascular diseases. The observed reduction in cardiovascular morbidity and mortality cannot only be explained by lipid-lowering only. Apart from lowering cholesterol, statins conceivably also exert effects on the vascular wall that may directly contribute to decrease of vascular incidents: (a) a favourable influence on endothelial dysfunction through stimulation of nitrous oxide synthetase: (b) stabilization of plaques by reducing influx of macrophages into the vascular wall and decreasing the production of matrix metalloproteinases, that may affect the connective tissue cover of the plaque: (c) inhibition of the initiation and progression of atherosclerosis by reducing adhesion of leukocytes to the vascular wall: (d) reducing the haemorrhagic diathesis by increasing the fibrinolytic capacity and inhibiting tissue factor expression on macrophages. All these effects of statins independent of the lowering of the cholesterol level might contribute to primary and secondary prevention of vascular incidents. While most nonlipid mechanisms of statins are being studied in vitro and in animals, the clinical relevance is still to be determined.