Delirium is the presenting feature in a few stroke patients, but can complicate the clinical course of acute stroke in up to 48% of cases. Old age, extensive motor impairment, previous cognitive decline, metabolic and infectious complications, and sleep apnoea are all predisposing conditions for delirium. Patients with delirium have longer hospitalizations and a poorer prognosis, and are at increased risk of developing dementia. The identification of the patients at risk and non-pharmacological preventative interventions are the key measures in the management of delirium. Curr Opin Neurol 15:51–55. © 2002 Lippincott Williams & Wilkins.