Delirium is a common condition in both inpatient and outpatient settings usually caused by a physical illness. Its one-year prevalence increases with age ranging from 22 to 31%. Numerous studies have shown that early diagnosis leads to rapid improvement, decreased hospital stays and long-term complications. In order to explore the agreement between the reasons of liaison consultation and final diagnosis of delirium, we performed a retrospective analysis of 1106 records corresponding to all elderly inpatients referred to the psychogeriatric liaison consultation of the University Hospitals of Geneva during one year. Among the 44 patients with suspected delirium, the diagnosis was confirmed by the liaison psychiatrist only in 41% of cases. Conversely, a final diagnosis of delirium matched to the reason of consultation only in 24.3% of cases. These observations show that the identification of delirium remains a difficult task.