In the frame work of a cross sectional study n=40 patients with mostly minor to moderate degree type I von Willebrand Jurgens syndrome (vWJ syndrome) were examined. Besides examining the concentration and activity (reduced by 20 to 40%) of the von Willebrand factor including the multimere analysis, the factor VIII activity and factor VIII antigen in these patients we also determined the PTT, the coagulation time and microscopically examined the nail fold capillaries. This showed morphological and dynamic changes of the microcirculation in comparison to a collective of n=100 apparently healthy subjects. Where as the capillary density was within the physiological limits 38 of the 40 patients showed a markedly increased torquation. 30 of the 40 patients presented dilated arteriole and venous branches of the capillary in part very marked. It was of particular interest that we observed extravascular blood cells and blood bands surrounding the capillary in 16 of the 40 patients. 33 patients had a discontinuous and discordant capillary perfusion at rest and in 10 patients a stagnation of flow was observed. 30 patients presented a lower mean capillary erythrocyte velocity than according to norm and 24 patients had a decreased vasomotor reserve. All patients examined showed changes in the capillary morphology. The correlation between the clinical data and the laboratory and capillary microscopic findings shown here stress the high sensitivity of the capillary microscopy.