The article deals with studying the degree of increase of the von Willebrand factor and the concentration of endothelin-1 in blood plasma in the subgroups of patients with diabetes mellitus formed depending on of type of disease and presence of phenotype with affection of kidneys. The sampling of 176 patients with diabetes mellitus (65 patients with diabetes mellitus type 1, 111 patients with diabetes mellitus type II) was examined. The control group consisted of 30 healthy persons. In the capacity of biochemical markers of endothelium dysfunction the activity of the von Willebrand factor and the concentration of endothelin-1 in blood were considered. In all patients with diabetes mellitus the biochemical characteristics of endothelium dysfunction are present manifesting by increase of concentration of endothelin-1 in blood which is especially expressed under disease phenotype with affection of kidneys. Despite of the apparent lesion of endothelium in patients with diabetes mellitus compromised with diabetic nephropathy the thrombocytes aggregation induced by ristomicine does not undergo natural changes. Hence, to consider in these patients the increasing activity of the von Willebrand factor as a reliable marker of endothelium dysfunction is not seemed possible.