Geriatricians use the phrase "geriatric syndrome" to describe the unique features of common health conditions in older people that do not fit into discrete disease categories. These conditions include delirium, falls, incontinence, and frailty. Geriatric syndromes share many common features. They are highly prevalent in older adults, especially frail older people. Their effect on quality of life and disability is substantial. Multiple underlying factors, involving multiple organ systems, tend to contribute to geriatric syndromes. Frequently the primary symptom is not related to the specific pathological condition underlying the change in health status. For example, when an infection involving the urinary tract causes delirium, it is the altered neural function in the form of cognitive and behavioral changes that permits the diagnosis of delirium and determines many functional outcomes. Because these syndromes cross organ systems and transcend discipline-based boundaries, they challenge traditional ways of planning and delivering clinical care.