Cushing's Syndrome (CS) may sometimes lead to dilated cardiomyopathy, even though this condition can be partially or completely reversed after treatment. In this article we report the case of a 28-yr-old woman with CS secondary to adrenal adenoma who exhibited congestive heart failure as an initial symptom. Two weeks before being admitted to our hospital, the patient started complaining of shortness of breath, orthopnea, paroxysmal nocturnal dyspnea and generalized edema. A physical examination did not reveal signs of hypercortisolism. Chest auscultation revealed bilateral diffused crepitation; blood pressure was 180/120 mmHg with heart rate of 90 beats/min. A chest X-ray showed a cardiac shade enlargement due to congestive heart failure. Transthoracic echocardiography demonstrated a dilated left ventricle and an impaired left ventricular systolic function. The patient's urinary cortisol excretion was elevated and circadian rhythm of cortisol was absent. ACTH level was low. In addition, plasma cortisol failed to decrease after administration of dexamethasone. An abdominal magnetic resonance imaging scan showed a 7-cm right adrenal mass. The patient was administered oxygen, spironolactone, ACE-inhibitor and the signs and symptoms of heart failure gradually improved. A laparoscopic right adrenalectomy was performed and pathological examination of the gland showed a benign adrenocortical adenoma. After the adrenalectomy the patient was started on hydrocortisone therapy and 5 months later the wall thickness of the left ventricle was within normal range and the patient's blood pressure was 130/80 mmHg. In conclusion we report the case of heart failure as the main clinical symptom in CS secondary to adrenal adenoma.