Objective: To examine the characteristics of all individuals assessed as requiring nursing home care arising from a population living within a defined geographical region and to study the manner in which they presented for assessment. Design: Clinical assessment by a physician in geriatric medicine with the assistance of other disciplines. Setting: Regional Geriatric Assessment Service. Subjects: All persons recommended for nursing home care within the study period. Results: The major diseases contributing to the need for nursing home care were organic brain disorders (60%) and stroke (32%). Dementia was present in 64% of cases; significant behavioral disturbance in 18%; severe communication disorders were frequent. The majority (86%) had been ill for greater than 1 year. The mode of presentation was acute in 9%, acute-on-chronic in 46%, and chronic in 45%. It was associated with significant differences in case characteristics including the location at the time of assessment, diagnoses, duration of illness, physical dependency, communication disorders, behavioral disturbance, and skilled nursing care requirements. Conclusions: These observations suggest that progression to nursing home care varies considerably. Strategies directed toward the prevention of institutionalization should be organized in recognition of these variations.