OBJECTIVES: To investigate whether underweight, normal-weight, overweight, and obese older adults differ in aspects of their oral health-related quality of life (OHRQoL). DESIGN: Cross-sectional study using a 54-item OHRQoL questionnaire. SETTING: Five counties in central Alabama: Jefferson and Tuscaloosa (urban), and Hale, Bibb, and Pickens (rural). PARTICIPANTS: The 291 subjects were recruited from participants in the University of Alabama at Birmingham Study of Aging, a longitudinal study of mobility. Participants ranged in age from 65 to 90 (60.5% women, 50.5% non-Hispanic white, and 50.5% rural). MEASUREMENTS: Participants completed an in-home interview about their OHRQoL using a 54-item questionnaire and were classified into four categories of body mass index (BMI) (<20.0 (underweight), 20.0-24.9 (normal), 25.0-29.9 (overweight), and ≥30.0 (obese)). Multivariate analyses were used to examine associations between BMI and OHRQoL, adjusting for age, race, sex, depression, education, perceived income, comorbidity score, life-space mobility, and physical activity level. RESULTS: The results suggested that a parabolic effect existed, with strongest associations occurring in the underweight and obese categories. With the normal BMI group as the reference group, obese participants were more likely to avoid eating foods they would like to eat, overweight participants were less likely to cook foods differently and reported better chewing ability, and underweight persons were more likely to limit foods they eat because of mouth dryness. CONCLUSION: Objective measures may not accurately reflect peoples' perceptions; therefore, OHRQoL determined according to response to subjective questions is important to properly assess a patient's overall health status. Older adults who are under- or overweight should be evaluated for oral health conditions that may affect their nutritional status. © 2007, The American Geriatrics Society.