Acquired factor VIII deficiency in women postpartum due to a factor VIII inhibitor is rare and the etiology is unknown. In this study a case report and a review of the literature are given. The haemorrhagic diathesis resembles classic haemophilia, with the exception that ecchymoses and tissue bleeding occur more frequently. The potency of the inhibitor may vary from weak to strong and the inactivation of factor VIII coagulant activity (factor VIII-C) by the inhibitor is of a non-linear type. Severe bleeding has been fatal in a few cases, but factor VIII concentrate substitution has usually been successful without anamnestic response of inhibitor activity. There is no convincing evidence that immunosuppression is effective, also because the natural history of the disease is characterised by a spontaneous disappearance of the factor VIII-C inhibitor. Treatment of bleeding symptoms with factor VIII concentrate should therefore not be reserved for life threatening haemorrhages only.