Carotid intima-media thickness (CIMT) can be measured non-invasively by means of B-mode ultrasound. Carotid ultrasonography is readily available and enables the assessment of the full spectrum of the atherosclerotic process, from normal artery walls to arterial occlusion. In population studies, CIMT correlates with present and future cardiovascular disease (CVD). The method has been well validated in histological and epidemiological studies. Controlled clinical trials have shown the value of CIMT as a surrogate marker to evaluate established therapies and novel anti-atherosclerotic drugs. At present, CIMT is increasingly being used as a surrogate aimed at reducing CVD risk at an individual level. In this paper we discuss the potential usefulness of CIMT as a risk marker in clinical programmes of CVD prevention.