A case of a young patient admitted to our hospital due to acute myocardial infarction is presented. Coronary angiography revealed normal coronary arteries. Echocardiography performed immediately after coronary angiography showed the presence of the left atrial myxoma. Three days later the patient underwent urgent surgery with a favourable outcome. The role of echocardiography in detecting atrial myxoma and mechanisms of myocardial infarction caused by this anomaly are discussed.