The title of the article by Pier Mannuccio Mannucci entitled “Bleeding symptoms in heterozygous factor VIII deficiency”, which appeared in the September 2010 issue of Haematologica ( volume 95, e6, doi:10.3324/haematol.2010.028969), was wrong and must be read as “Bleeding symptoms in heterozygous factor XIII deficiency”. We apologizes to the author for this mistake.