A high proportion of adults admitted to hospital experience delirium, a pathological alteration in cognition associated with inattention, a fluctuating course, and an underlying systemic illness, metabolic imbalance, or association with drug. Delirium has been linked to adverse short term outcomes, including up to threefold increases hospital mortality and length of stay, which place considerable burdens on caregivers and healthcare services. Delirium can also have long term consequences, with studies indicating an association between delirium and a higher likelihood of death, functional disability, admission to residential care, cognitive impairment, and dementia after discharge. Delirium can be overlooked, misdiagnosed, and its significance underestimated by healthcare providers working in intensive care. Nurses Knowledge and practices of the true magnitude of delirium and its associated burdens in critically ill patients would allow clinicians, researchers, and policymakers to allocate much needed resources towards reducing morbidity and mortality associated with delirium.