Measurement of oxygen consumption (OC) has been less than satisfactory in patients with heart failure. This has necessitated the invasive techniques to measure the total oxygen demand with cardiopulmonary exercise (CPX). The present study proposes a novel method to quantify OC using BOLD effect of oxygen-inhalation T2* MRI. Difference between oxygen-T2* and room-air-T2* (ΔT2*) was identified as an estimate of OC. ΔT2* was significantly correlated with systematic and myocardial OC expressed as the results of CPX and myocardial fatty acid scintigraphy. Our method allows assessing non-invasively OC in vivo. ΔT2* could be used as an imaging biomarker for heart failure.