Obstructive Sleep Apnea Syndrome (OSAS) is a frequently occurring childhood malady, whose is incidence is largely underestimated, that can lead to serious complications. Because of their understanding of the anatomy and physiology of the masticatory apparatus and of the upper airways, orthodontist are in a strategic position to detect in their young patients developing disorders in these regions; accordingly when they suspect the existence of OSAS they should ask systematic and well targeted questions of parents who may not be aware of the relationship between certain symptoms their children display and sleep breathing problems. The goal of this article is to provide practitioners with a better understanding of the symptoms and the physio-pathological mechanics of OSAS so that they can spare their afflicted patients the complications it provokes by seeing that early treatment is undertaken.