Most coronary arteriovenous fistula (CAVF) drain into the pulmonary artery or the right heart chamber. CAVF between the left coronary artery and left ventricle is very uncommon. Moreover, a case of CAVF from a diagonal branch of the LAD to the LV has not been reported so far. We report a case of a 79-year-old man, complaining of intermittent chest pain and dyspnea on exertion for apprioximately 2 months. CAVF from the diagonal branch of the LAD to the LV was confirmed by selective coronary angiography.