Despite the fact that the treatment for heart failure has advanced with evidence of reduction in the morbidity and mortality, the condition is still often associated with poor outcome. Although exercise testing is seen as dangerous to the patients with heart failure but recent evidences show that exercise has beneficial effect in improving functional activity as well as the quality of life of the patients. In patients with heart failure, resting ventricular function parameters are not always correlate with exercise capacity. Because patients first experience dyspnea and fatigue during activity, it is important to assess the functional capacity of the confirmed or suspected heart failure to confirm if such impairment exists. This study provides the usefulness of estimated oxygen consumption in the evaluation of functional capacity in patients with chronic heart failure. The outcome has implication for patients monitoring and prognosis.