['Although Behavioral and Psychological Symptoms of Dementia (BPSD) increase with increasing dementia severity, and institutionalization of an individual with dementia is often caused by behavioral symptoms, relatively few studies have explored the prevalence of BPSD in nursing homes.', 'To study the prevalence and correlates of agitation in residents with dementia, in Norwegian nursing homes.', 'This study has taken place in dementia wards in four Norwegian nursing homes. To measure agitation in residents with dementia we used the Cohen-Mansfield Agitation Inventory (CMAI), consisting of 29 agitation items. Dementia stage was measured by Functional Assessment Staging (FAST).', 'Two hundred and eleven patients (71% female) were included in the study: mean (SD) age 85.5 (8.4), FAST 4.7 (2.1), CMAI total sumscore 39.5 (12.6). Dementia was present in 167 (79%) subjects. Among those with dementia, weekly occurrence of at least one CMAI item (i.e. a score of 3 or higher) occurred in 75.4% (95% CI 68.4-81.4). Six of the items occurred at least weekly in 20% of the residents with dementia, and 11 of the items, including physical aggression, occurred in less than 5% of the residents. Agitation was associated with more severe dementia (p = 0.001), but not with age and gender.'] Does prevalence and correlate of disruptive behavior in patients in Norwegian nursing homes?