B ad teeth alignment could affect people’s confidence and how others behave around them. Maloclusions are more likely occur in people with mental retardation, for example Down Syndrome. Down Syndrome is an congenital genetic anomaly, an autosomal chromosomal anomaly with high prevalence of class III Angle malocclusion, crossbite, crowding and also open bite. The purpose of this literature review was to describe the orofacial characteristic and malocclusion found in Down Syndrome patients and several consideration that should be done to treat them. Several problems might appear in the orthodontic treatment because of oral problems, mental and behavioural factor. Down Syndrome patient could be treated with orthodontic treatment but this treatment should be well-considered because of the behavioral problem. Down Syndrome patient with mild and moderate mental retardation, whose still could communicate well and well-behaved, can be treated with orthodontics. Preffered case to be treated with orthodontics are malocclusions with hypotonic masticatory muscles and tongue muscle resulting in breathing and swallowing disturbance. Good diagnostic, behavior management, and cooperation amongs dentist, patient and parents is the key to a successful orthodontic treatment in Down Syndrome patient.