Background: several studies examining diet and functional status of individuals have focused on single nutrients or food groups. Studies examining the relationship between diet and health have increasingly witnessed a shift in focus from single nutrients to overall diet quality. The objective of this study was to examine the association between overall diet quality and self-reported disability. Setting: the 1999-2004 National Health and Nutrition Examination Survey (NHANES). Subjects: a nationally representative sample of Americans ≥60 years. Methods: overall diet quality was assessed using the United States Department of Agriculture's (USDA) Healthy Eating Index-2005 (HEI-2005). Self-reported measures of disability included activities of daily living (ADLs), instrumental activities of daily living (IADLs), leisure and social activities (LSAs), lower extremity mobility (LEM) and general physical activities (GPAs). Results: older adults with higher HEI-2005 scores were less likely to experience LEM (P for trend=0.001) and GPAs (P for trend<0.001) disability. Compared with older adults whose HEI-2005 scores were in the lowest quartile, the likelihood of both IADLs and GPAs disability were significantly lower in those with HEI-2005 scores in quartiles two, three and four. Compared with those who had HEI-2005 scores in the lowest quartile, the odds of LEM disability were significantly lower for those with HEI-2005 scores in the highest quartile. Conclusion: older adults who do not adhere to the 2005 Dietary Guidelines for Americans report disability more frequently than those who do adhere to the guidelines. © The Author 2011. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved.