This study determines whether prevalence and predictors of nursing home admission changed in the 1990s, during a period of dramatic changes in the service provision for and medical care of chronic impairments. Data from the 1993-2000 surveys of the Asset and Health Dynamics Among the Oldest Old (AHEAD) Study, a longitudinal and nationally representative sample, were used. Proportional hazard models were used to determine the effects of dementia, physical functioning, clinical conditions, and sociodemographics on the likelihood of nursing home admission. Of the 6,676 respondents, 17% were admitted to a nursing home. Models excluding functional impairment demonstrated significant effects of chronic medical conditions and dementia on the risk of institutionalization. After controlling for functional impairment, dementia still had significant and strong effects on institutionalization but clinical conditions did not, suggesting that the impact of dementia goes beyond its effect on physical functioning. Nursing home admissions did not decrease during the study period, and the impact of dementia on the risk of nursing home admission did not decrease. Interventions for individuals with dementia should impact the behavioral aspects of the condition and slow disease progression in addition to improving physical functioning. (C) 2004 Lippincott Williams & Wilkins, Inc.