Pheochromocytoma is a benign catecholamine secreting tumor, which is rare and originates from the adrenal gland. It has been known for a wide range of clinical manifestations and can mimic other difficult-to-diagnose diseases. Here, we report a female patient with acquired long QT syndrome, which is a rare complication of pheochromocytoma. Although relatively rare, the presence of pheochromocytoma should be considered in the case of malignant arrhythmias and electrocardiographic changes in patients.