We report a case of hypercalcemia in an elderly patient due to vitamin D intoxication with clinical features and electrocardiogram (ECG) findings mimicking acute myocardial infarction. A 78-year-old man was referred to our department with symptoms of general fatigue, anorexia and chest pain. The ECG demonstrated ST elevation in leads V1 to V3 and diffuse T wave flattening, resulting in myocardial infarction being suspected. However, his symptoms, including chest pain, gradually improved and the ECG returned to normal in accordance with a fall in his serum calcium level. We introduce the use of QaTc interval shortening in differentiating ST-T changes of hypercalcemia from those of true myocardial ischemia.