We describe a case of a very anomalous origin of the left main coronary artery, misdiagnosed as occluded at previous invasive coronary angiography. Multidetector computed tomography coronary angiography demonstrated the vessel to be patent, with an anomalous origin from the commissural region between the right sinus of Valsalva and posterior sinus of Valsalva. A large coronary fistula between proximal left anterior descending coronary artery and the right sinus of Valsalva was also demonstrated. This is an example of the additional clinical role of multidetector computed tomography coronary angiography in comparison to conventional coronary angiography in this clinical field.