We report a case of a right atrial myxoma initially presenting as an acute anteroseptal MI. A 46-year-old man has been admitted to our ICU with chest pain started five hours before. The initial ECG showed sinus rhythm 56/min with normal atrioventricular conduction and ST segment elevation of 3-4 mm in leads V1-V2, T wave inversion pattern in leads I, II, aVL, V3-V6 with loss of R- voltages in leads V2, V3 all suggestive of an anterior wall myocardial infarction. Total serum creatine kinase (CK) and CK-MB isoenzyme were normal, troponine I and T measurement were not available in our laboratory at that time. Patient received thrombolytic therapy (i.v. Streptokinase 1.5 x 106 U) over 60 minutes without succes. During and after thrombolytic therapy, ECG changes or increased values of cardiac enzymes were not detected. Next morning the patient was reffered for echocardiography. Transthoracic echocardiography showed normal left ventricular contractility and normal ejection fraction. Transesophageal echocardiography showed a large right atrial sessil mass (50 mm x 36 mm) arising from the interatrial septum. Coronary angiography confirmed moderate left ventricular enlargement with normal ejection fraction with normal coronary arteries. Patient underwent cardiac surgery. The tumor was adherent to the atrial wall in the region of the fosa ovalis, and completely removed. Histology confirmed that tumor was myxoma. The patient had an uncomplicated recovery.