Acquired von Willebrand syndrome is a bleeding disorder associated with various underlying diseases. The clinical manifestations are similar to congenital von Willebrand disease. Diagnosis is mainly confirmed by decrease of ristocetin cofactor activity (vWF:RCo) and collagen binding activity (vWF:CBA) and by vWF multimeric analysis usually with selective loss of large multimers. Various pathogenic mechanisms have been proposed, including development of autoantibodies to von Willebrand factor (vWF), adsorption of vWF onto tumor cells or activated platelets, increase of vWF proteolysis, and mechanical destruction of vWF under high shear stress. Following the treatment of underlying disorders, desmopressin (DDAVP) is a first intention therapeutic option. Factor VIII/vWF concentrates and high dose immunoglobulin infusions are reserved for patients unresponsive to DDAVP.