We encountered 2 patients with thyrotoxicosis accompanied at its onset by progressive angina. The ST segment was elevated in one patient and depressed in the other patient during the spontaneous attacks. Coronary arteriographic findings were normal during control, and spasm was induced by ergonovine. No patients had chest pain even without antianginal medication after successful treatment of thyrotoxicosis. The coronary artery may become sensitive to spasm during thyroid hormone excess even in cases without significant coronary artery disease and previous chest pain.