Case-control and cross-sectional studies show that some common molecular variations (polymorphisms) of genes coding for proteins involved in atherosclerosis and thrombosis are often present in subjects who have experienced cerebrovascular or cardiovascular events. The clinical impact of the majority of polymorphic markers is disputed by prospective reports. In contrast, their pathophysiological implications and their role in monitoring parameters that are difficult to be checked by alternative means, are documented by the large majority of the reports. From the evidence available, there may be suggestion for further impact of polymorphic markers in vascular medicine. To substantiate this, new prospective studies that include individuals from different geographical areas and that take into account the statistical power, the informativeness of the markers, the coexistance of established risk factors and the genetic background of the populations analyzed, are urgently needed.