A 54-year-old woman with occlusive disease of the distal abdominal aorta was referred for pre-operative risk assessment, and was diagnosed with severe impairment of the left ventricular function due to left main stem coronary artery stenosis. Low-dose dobutamine stress echocardiography did not demonstrate contractile reserve, while gadoliniumenhanced cardiac magnetic resonance (CMR) suggested viability of the left ventricle. The patient underwent coronary bypass grafting, and had an uncomplicated post-operative course, with improvement of the left ventricular ejection fraction from the initial 20% to 44% after four months. The value of CMR in determining myocardial viability in left main stem stenosis has not previously been reported.