We report a case of an anomalous origin of left coronary artery from the pulmonary artery with severe mitral regurgitation. A 20-year-old female was admitted to hospital for recurrent syncope and dyspnea on exertion. Cardiac ausculatation revealed systolic murmur radiating to left axilla and blood pressure of 90/70 mmHg. Electrocardiography showed a nonspecific ST-T wave change on V1, V2, V6, I, & aVL leads. Holter monitering showed no significant abnormality except occasional premature ventricular complexes. Chest radiography showed mild cardiomegaly with mitral valvular heart configuration and no pulmonary abnormality. Echocardiography showed normal left ventricular dimension and systolic function with marked dilated left atrium, severe mitral regurgitation, & severe resting pulmonary hypertension. Aortogram didn't show left coronary artery ostium. Right coronary angiogram showed normal right coronary artery which supplied major left epicardial coronary arteries via good collaterals (Rentrop grade III). Pulmonary angiogram showed anomalous origin of left coronary artery from main pulmonary trunk. She underwent mitral valvuloplasty and coronary artery bypass graft.