The past decade has seen the completion of a series of prospective epidemiologic studies evaluating the association between haemostatic factors and cardiovascular diseases. All the studies agree that fibrinogen is a strong, independent cardiovascular risk factor. Various cross-sectional studies have revealed numerous interactions between fibrinogen and other risk factors. However, our understanding of these interrelations is still incomplete. A broad pathophysiologic basis and the results from clinical studies further argue for a crucial role of fibrinogen in atherothrombogenesis.