The history of Ambulatory Anaesthesia is almost as old as Anaesthesia itself. In recent years different models and settings for Ambulatory Anaesthesia care have been developed especially in the USA. Economic benefits are potentially large although there are controversies around the settings for care. Operating room utilisation should be maximised including reappraisal of traditional selection criteria. Many are pushing back the boundaries of selection criteria for example for obese patients or patients with Obstructive Sleep Apnea.