Sleep is an integral part of human existence and is now, more than ever, the subject of clinical and research interest. Why do we spend approximately one third of our lives asleep? Sleep probably has a recovery function, especially for the brain. Throughout rapid eye movement sleep, neuronal connections in the catecholamine system are created, and this activity is essential to maintain cognitive function.w1 During rapid eye movement sleep in particular, the body is at its most relaxed state, and a three dimensional collapse of muscle (musculus genioglossus and musculus geniohyoideus) and fatty tissue around the upper airway may cause obstruction.1 When a pre-existent narrowing and slackening of the upper airway is also present, 2 apnoeas (complete cessation of breathing for 10 seconds or more) or hypopnoeas ( > 50% diminishing of airflow or oxygen desaturations > 3% for 10 seconds or more) may result. The prevalence of obstructive sleep apnoea in middle age is 2% for women and 4% for men.3 In practice, obstructive sleep apnoea seems to be under-reported; obstructive sleep apnoea is undiagnosed in an estimated 80% of patients. 4 Patients with obstructive sleep apnoea are particularly vulnerable during anaesthesia and sedation. w2This is not only the case for operations or other invasive interventions aiming at alleviation of obstructive sleep apnoea through reduction of the obstructive upper airway; even after surgery not related to obstructive sleep apnoea, such as hip and knee operations, patients with obstructive sleep apnoea are at risk of developing respiratory and cardiopulmonary complications postoperatively. Serious complications include reintubations and cardiac events.6 Anaesthetic management must focus on and deal with the increased likelihood of morphological alterations of the upper airway leading to an increased rate of difficulties in securing and maintaining a patent airway. 7In this review we discuss the various anaesthetic aspects of obstructive sleep apnoea, including preoperative, perioperative, and postoperative points of special interest. We also cover the various management options.