Purpose: We sought to characterize self-neglect definitively as a geriatric syndrome by identifying an association with functional impairment. Design and Methods: We performed a cross-sectional home evaluation of 100 community-living older adults referred by Adult Protective Services for geriatric self-neglect and 100 matched adults from a community geriatrics clinic. We made our assessments by using two manual muscle tests, a timed-gait test, a modified Physical Performance Test (mPPT), and the Kohlman Evaluation of Living Skills (KELS). Results: Participants in the self-neglect group had impaired mPPT (p less than 0.077) and KELS (p less than 0.001) scores compared with community-controls. Using analysis of covariance models, we found that self-neglect referral explained a significant proportion of the variance in KELS scores (32%; p less than 0.001) but not in mPPT scores (22%; p = 0.49). Implications: The geriatric syndrome of self-neglect is associated with increased morbidity and mortality and appears to be independently associated with impairments in instrumental activities of daily living. The evaluation and treatment of geriatric self-neglect should be consistent with that of other geriatric syndromes.