The vascular endothelium, building the inner layer of capillaries and brood vessels of all sorts, represents a highly active metabolic and endocrine organ producing a multitude of different molecules, including vasoactive peptide hormones, growth factors, coagulation factors and adhesion molecules. In addition, it expresses many of the respective endocrine, paracrine and cytokine/growth factor receptors. It thereby regulates the delicate balance between vasoconstriction and vasodilation, between coagulation and fibrinolysis, proliferation and apoptosis, as well as between transient adhesion and diapedesis of blood borne leukocytes. This minire-view addresses the potential interactions of these important functions in the states of diabetes and of insulin resistance including obesity, hypertension and dyslipidaemia, all of which characterized by endothelial dysfunction.