BACKGROUND:Moebius syndrome (MS) is a rare congenital condition that is characterised by facial hypomimia and congenital strabismus caused by complete or partial impairment of the 6th and 7th cranial nerves. MS may be further associated with other nerves or malformations, mainly involving the extremities. The objective of this study was to quantify the decrease in oral motor performance in people with MS compared with normoreactive individuals using the Oral Motor Assessment Scale (OMAS). METHODS:The study group comprised 33 subjects between the ages of 2 and 20 years (average age: 10 ± 5 years) with MS along with 46 age- and gender-matched control subjects. RESULTS:The study group displayed a lower average functional score than the control group (P < 0.0001). A significant lack of lip closure (P = 0.03) and anterior lingual seal during swallowing (P = 0.03) occurred in the study group; in most cases, the individuals with MS were classified as 'subfunctional'. In addition, individuals with MS in the older age group displayed better functional scores than those in the younger group (P = 0.05). CONCLUSIONS:Functional damage to oral motor function in individuals with MS is evident, but differs among patients with respect to severity and the movements that are compromised. However, overall, improvements in the functional patterns of these individuals can be observed as they mature in age.