Re: Acquired von Willebrand s syndrome resulting from untreated hypothyroidism in two prepubertal girls. A. Galli-Tsinopoulou, C. Stylianou, G. Papaioannou, S. Nousia-Arvanitakis. Haemophilia 2006; 12: 687–689. The authors present two patients with acquired von Willebrand s syndrome (AVWS) resulting from hypothyroidism and the review of previous literature relating to this subject matter. AVWS is a rare form of bleeding diathesis and the reasons of this haemostatic disorder are variable. Various mechanisms of acquisition have been investigated depending on the underlying disease. One of the pathogenetic mechanisms explains a decrease in von Willebrand factor (VWF) protein synthesis due to the absence of adequate levels of thyroxine [1,2]. There are few reported cases of hypothyroidism as a cause of AVWS. We would like to contribute a case of a patient with AVWS.