The prevalence of neuropsychiatric disorders and other medical illnesses was investigated in 65 nursing home residents. The authors found neuropsychiatric disorders to be present in 94% of the sample. The neuropathologic causes of these syndromes were found to be more diverse than in previous studies. The most frequent causes were degenerative, vascular, and toxic. The most common psychiatric syndromes that resulted from these neuropathologic disorders were dementia syndrome (72%), organic personality syndrome (14%), and organic psychotic disorders (12%). The most common behavioral problems, agitation and aggression, most likely reflected the high prevalence of frontal lobe damage and affected 48% of the sample. Other non-neuropsychiatric medical problems were significantly less common. While only 4% of the sample had no neuropsychiatric diagnosis, 39% had no other non-neuropsychiatric diagnosis. These results suggest that the nursing home is not used as a referral source for chronic medical conditions in general but almost exclusively for the care of chronic neuropsychiatric disorders.