the aims of SACHA study was to appreciate prevalence, evolution and follow-up, treatment response of patients with acquired hemophilia with biological and clinical data. Inclusion criteria were factor VIIIc below 30% associated with presence of Facgteur VIII inhibitor (titer > 1 u Bethesda. Clinical and biologival data were obtained at Day 0 (as soon as possible and at 1, 3, 6 and 12 months.Informations were notified to co-investigators with the help of two french medical society (Internal medicine, french haemostasis and thrombosis society.