The perioperative risk for patients with obstructive sleep apnea syndrome and the optimal anaesthesiological management of these patients have not been well elucidated. The prevalence of obstructive sleep apnea with significant symptoms is estimated to be 4% in men and 2% in women. However, in 80-95% of patients this syndrome is not sufficiently diagnosed. Thus identification of patients at risk and a thorough multidisciplinary diagnostic approach are essential for optimal perioperative management. The risk of perioperative complications, like cardiopulmonary compromise, and difficulties in airway management is elevated. The most important aspects of perioperative management include evaluation of intubating conditions, careful search for cardiopulmonary morbidity, permanent control of patient airways, sensible use of anaesthetics, sedatives, and narcotics, and strict monitoring of vital signs. If ambulatory nasal continuous positive airway pressure (CPAP) therapy has been established preoperatively, this should be continued in the perioperative period. Postoperative monitoring should be performed in an intensive care or intermediate care unit. Controlled clinical studies on the best perioperative management of patients with obstructive sleep apnea are urgently required.