OBJECTIVE: We studied the associations of cardiorespiratory fitness with metabolic syndrome in older men and women, because such data are limited in representative population samples. RESEARCH DESIGN AND METHODS: We studied a population sample of 671 men and 676 women aged 57-79 years at baseline of a randomized controlled intervention study. We assessed maximal oxygen uptake (Vo(2max)) by respiratory gas analysis during a maximal bicycle exercise test. RESULTS: Vo(2max) had a strong, inverse, and graded association with the risk of having metabolic syndrome as defined by the National Cholesterol Education Program criteria. Men and women in the lowest third of Vo(2max) had 10.2- and 10.8-fold higher risks and those in the middle third had 2.9- and 4.7-fold higher risks (P < 0.001 all) of metabolic syndrome than those with the highest Vo(2max) after multivariable adjustments. Factor analysis generated a principal factor that was strongly loaded by the main components of metabolic syndrome and Vo(2max) (-0.68 in men and -0.70 in women). CONCLUSIONS: Low cardiorespiratory fitness is associated with metabolic syndrome in older men and women. Our findings suggest that low cardiorespiratory fitness could be considered a feature of metabolic syndrome.