The most common congenital bleeding disorder is haemophilia. It is a pathology inherited and caused by a defective or an absence of the coagulation factors, so that haemophiliacs cannot form an efficient clot. These patients have been treated with fear in the dental profession without having achieved the goals and ideals most appropriate according to the requirements of each case, which is demonstrated in the little existing literature available. However, they are currently treated as healthy orthodontic patients thanks to the advances in orthodontics. We present the cases of two brothers with mild classical haemophilia, who were treated by Mc Namara's disjunctor. The emphasis is on importance of interconsultation with the haematologist, prevention and oral hygiene, and that of the beneficial effect of orthodontic.