Delirium (acute confusional state) is a common and disabling complication among surgical older people. It is often underdiagnosed and undertreated. Its incidence varies by type of intervention and it is associated with several complications such as functional impairment, cognitive dysfunction, prolonged hospitalization and institutionalization. These increase hospitalization costs and the risk of death. There are precipitating and predisposing risk factors, which increase the susceptibility for postoperative delirium. This condition should be considered as a syndrome of epidemiological importance, which needs to be prevented or treated in a timely manner through a multidisciplinary intervention. The perioperative care of elderly patients involves different medical specialties and is a subject of general knowledge.