Few studies have addressed the association between abdominal obesity, as measured by waist circumference (WC), and disability in the elderly. Moreover, those studies were cross-sectional and yielded inconsistent results. The objective of this study was to examine longitudinally the association between WC and self-reported disability among older adults. A prospective cohort study was conducted from 2001 to 2003 in 3235 persons (1411 men and 1824 women) representative of the non-institutionalized Spanish population ages 60 years and older. Baseline information was collected by home-based personal interviews and measurement of WC, weight, and height. Two years later, information on disability was obtained by telephone interview. The association of interest was summarized with odds ratios obtained by logistic regression. Among persons reporting no disability at baseline, WC predicted disability 2 years later. After adjustment for age, education, tobacco use, alcohol consumption, and physical activity, men in the highest WC quintile had 2.17 (95% confidence interval, 1.15 to 4.09) times more risk of mobility disability and 4.77 (95% confidence interval, 2.50 to 9.13) times more risk of agility disability than those in the lowest quintile. Additional adjustment for BMI, chronic diseases, and cognitive function led to only a slight reduction in this association. Results were similar for women. No statistically significant association was observed between WC and restriction of daily activities, limitation in instrumental activities of daily living, and limitation in bathing or dressing, in either men or women. WC predicts mobility and agility disability in old age. Avoidance of the highest values of WC might decrease the risk of disability in older adults.