The prevalence of neuropsychiatric symptoms and the influence of predictive factors in cognitively impaired nursing home patients were reviewed. Articles were identified by means of a MEDLINE and PsychInfo literature search. Neuropsychiatric symptoms were present in more than 80% of the cognitively impaired patients. Prevalences ranged considerably, from 3% to 54% for delusions, 1% to 39% for hallucinations, 8% to 74% for depressed mood, 7% to 69% for anxiety, 17% to 84% for apathy, 48% to 82% for aggression or agitation, and 11% to 44% for physical aggression. Neuropsychiatric symptoms seemed to be predicted not only by dementia type or stage but also by the psychosocial environment and the amount of psychoactive medication and physical restraints used. Neuropsychiatric symptoms are common and influenced by both the disease itself and the psychosocial environment of the institutional setting. The latter may have important consequences for staff planning and education and the future design of care facilities.