This paper reviews the advances in understanding of fibrinogen structure and function, its genetic and environmental determinants, role in the process of hemostasis, platelet aggregation, plasma viscosity and erythrocyte aggregation, cellular and matrix interactions, inflammation, wound healing, tumor development, atherogenesis and involvement in pathogenesis of diseases, that have been made over the past decade. Future studies will seek to define precise mechanisms of complex gene-environment interactions that influence fibrinogen levels and its complex role in the pathogenesis of fibrinogen-associated diseases.