Background A wide variety of instruments have been used to assess the functional capabilities and health status of patients with chronic heart failure (HF), but it is not known how well these tests are correlated with one another, nor which one has the best association with measured exercise capacity. Methods and Results Forty-one patients with HF were assessed with commonly used functional, health status, and quality of life measures, including maximal cardiopulmonary exercise testing, the Duke Activity Status Index (DASI), the Veterans Specific Activity Questionnaire (VSAQ), the Kansas City Cardiomyopathy Questionnaire (KCCQ), and 6-minute walk distance. Pretest clinical variables, including age, resting pulmonary function tests (forced expiratory volume in 1 s and forced vital capacity), and ejection fraction (EF) were also considered. The association between performance on these functional tools, clinical variables, and exercise test responses including peak VO 2 and the VO 2 at the ventilatory threshold, was determined. Peak oxygen uptake (VO 2) was significantly related to VO 2 at the ventilatory threshold ( r = 0.76, P < .001) and estimated METs from treadmill speed and grade ( r = 0.72, P < .001), but had only a modest association with 6-minute walk performance ( r = 0.49, P < .01). The functional questionnaires had modest associations with peak VO 2 ( r = 0.37, P < .05 and r = 0.26, NS for the VSAQ and DASI, respectively). Of the components of the KCCQ, peak VO 2 was significantly related only to quality of life score ( r = 0.46, P < .05). Six-minute walk performance was significantly related to KCCQ physical limitation ( r = 0.53, P < .01) and clinical summary ( r = 0.44, P < .05) scores. Among pretest variables, only age and EF were significantly related to peak VO 2 ( r = −0.58, and 0.46, respectively, P < .01). Multivariately, age and KCCQ quality of life score were the only significant predictors of peak VO 2, accounting for 72% of the variance in peak VO 2. Conclusion Commonly used functional measures, symptom tools, and quality of life assessments for patients with HF are poorly correlated with one another and are only modestly associated with exercise test responses. These findings suggest that exercise test responses, non-exercise test estimates of physical function, and quality of life indices reflect different facets of health status in HF and one should not be considered a surrogate for another.