Von Willebrand factor (vWF) is a large glycoprotein with a multimeric structure and a molecular mass ranging from 500 kDa up to more than 10,000 kDa, the latter being the largest known for a soluble human plasma protein. The primary product of the von Willebrand factor gene, located at chromosome 12p13.2, is a 2813 amino acid comprising a signal peptide of 22 amino acids, a large propetide of 741 amino acids, and a mature vWF molecule containing 2050 amino acids. Expression of the von Willebrand Factor gene is tissue specific and confined to endothelial cells and megakaryocytes. VWF is present in plasma, in the Weibel-Pallade bodies of endothelial cells, in the alpha-granule in megakaryocytes and platelets derived from them, as well as in the subendothelial matrix of the vessel wall. VWF serves as a carrier for factor VIII in plasma, protecting the circulating coagulation coenzyme from proteolytic degradation. The von Willebrand disease is the most common bleeding disorder affecting 1% of the population and is caused by the qualitative or quantitative deficiency of vWF. It is classified into 3 main types: Type 1 is a partial quantitative deficiency; Type 2, is a qualitative defect which is further subdivided into four categories; and Type 3 is a complete absence of vWF.