Sixty-five consecutive patients with dementia, treated at a psychogeriatric day hospital, were studied regarding prevalence of psychiatric symptoms. The clinical diagnoses were dementia of the Alzheimer type (n = 19), vascular dementia (n = 27), mixed Alzheimer's disease and vascular dementia (n = 13), vascular dementia of frontal type (n = 2), and other diseases (n = 4). Mean age at referral was 75.6 ± 6.6 years and the average treatment time was 21 ± 14 months. About 90% of the patients showed one or several significant psychiatric symptoms during the course of dementia. Most common were delirious episodes, anxiety, sleep distrubances, and depressed mood. The relationship between clinical features and the type and duration of dementia was analyzed. Sleep disturbances and depressed mood often appeared early, whereas misidentification and delusions became more prevalent later in the course of dementia. The results indicate that the psychogeriatric day hospital may offer effective and flexible care and support to demented persons living at home.