Introduction: Obstructive Syndrom Apnea (OSA) has a worldwide incidence of 0.3 to 5%, predominantly in men. This pathology causes an obstruction of the upper airway with a significant risk of asphyxia and sudden death. The objective of our study was to report the case of a patient with OSA treated in Dento-Facial Orthopedics. Observation: This was a 41-year-old man with risk factors for OSA, dento-arch dysmorphosis, and maxillo-mandibular bone deformity. The nasofibroscopy revealed a narrowed oropharynx, an airway obstruction in the supine position. The polysomnography concluded to the diagnosis of OSA in its severe form with 45 apneas in one night, an oxygen saturation of 85%. The treatment consisted of a mandibular advancement prosthesis. Discussion: OSA is a serious pathology under-diagnosed in Madagascar. Repeated apneas and hypopneas are associated with significant decreases in oxygen partial pressure. The most reliable and widely used test in the world is polysomnography. Treatment of OSA with positive pressure allows the increase of the pressure inside the pharynx. Mandibular advancement prostheses allow for promandibulia. These therapeutic devices improve the quality of life of our patient. By traction system, the device allows a mandibular protrusion during sleep. Conclusion: The treatment of OSA consists of a multidisciplinary management including Dento-Facial Orthopedics and dental prosthesis.