Obstructive sleep apnoea, OSA, is formally defined as an apnoea-hypopnoea index (AHI) of at least 5 episodes/hour (mild). Obesity, alcohol, smoking and sedatives may contribute to the development of OSA, as well as tonsilar hypertrophy and maxillary and/or mandibular retrognathia. Endocrine conditions such as hypothyroidism and acromegaly have also been reported associated with OSA. Except for excessive daytime sleepiness, headaches and irritability, OSA may lead to hypertension, heart failure, MI and stroke. Management involves reduction of predisposing factors such as obesity and alcohol. Treatment with continuous positive airway pressure (CPAP) is currently most common and best documented. Also uvulopalatopharyngeal surgery and so called phase II surgery, which means advancement of the jaw(s) with orthognatic surgical methods are used. Treatment with dental appliances is getting increasingly popular but the long term outcome remains debatable.