Despite the training and skills of airway managers, airway management complications still occur and may cause patient harm or death. The causes are multifactorial and may include patient, environment and clinician factors. Airway complications likely contribute to a significant proportion of deaths due to anaesthesia and are certainly more common outside the operating theatre and especially in the critical care unit. Reported incidences of failure and harm during airway management vary depending on the population studied and definitions used. Numbers may be of less value than understanding themes that help us improve care and reduce harm. The chapter emphasises that conventional research (e.g. device evaluation studies and randomised controlled trials) may be of little use in identifying low frequency events and complications because of their restricted inclusion and exclusion criteria, the use of devices only by experts and in conventional settings and because of their focus on efficacy rather than safety. The chapter highlights the important and growing role of registries and databases. Several are described in detail including the 4th National Audit Project and the Dutch ‘mini-NAP’. The value and limitations of litigation databases are explored. Specific complications of note are described at the end of the chapter.