The author describes a case of a patient with haemopericardium during the acute stage of myocardial infarction. In the echocardiographic tracing since the development of the tamponade a thrombus was seen in the pericardial cavity, its organization and gradual complete absorption in the course of a one-year follow up. The finding of echogenic masses in the pericardial cavity containing fluid is highly specific for hemopericardium.