Cigarette smoking is known to be a strong risk factor for several cardiovascular diseases such as ischaemic heart disease, stroke, intermittent claudication and aortic aneurysm. Atherosclerosis, often with superimposed thrombosis, has been shown to be the underlying disease process in all of these diseases. This fact has led to the assumption that smoking accelerates the atherosclerotic process and thereby promotes premature cardiovascular disease. However, increased occurrence of smoking-mediated thrombosis might also play a causative role. This review therefore considers clinical and experimental evidence regarding the atherogenicity and thrombogenicity of cigarette smoking in the development and occurrence of cardiovascular disease. On the basis of the currently available literature, it is concluded that evidence for the atherogenetic effect of smoking is scarce, and that the effect on the athrosclerotic process in the coronary arteries is only moderate if present at all. On the other hand, both clinical and experimental data strongly support the notion that thrombogenetic factors are responsible for the increased occurrence of ischaemic heart disease, and particularly acute coronary syndromes, among chronic smokers.