Genetic factors are important in the pathogenesis of cerebrovascular diseases. Stroke represents a multifactorial polygenic disorder where the role of environmental factors is quite well defined as opposed to the role of genetic factors which needs to be further elucidated. Several genes affecting hemostasis, renin-angiotensin system, nitric oxide production, homocysteine metabolism and lipid metabolism have been investigated in stroke even if with conflicting results. The genetic approach could permit, in the future, a better characterization of stroke patients and a more effective individual preventive and therapeutic approach.