Patients with traumatic rupture of the pericardium rarely survive to reach a hospital. Ten cases from the Maryland Institute for Emergency Medical Services Systems and 132 previously published cases are reviewed. Patients were usually men who were victims of violent thoracic trauma. The median age was 40 years. Half of the patients had left pleuropericardial tears; tears of the diaphragmatic pericardium, right pleuropericardium, and superior mediastinal pericardium were less frequent. Associated injuries of the heart or left hemidiaphragm were common. Pericardial rupture was usually discovered during surgical exploration for other indications, but physical or radiographic signs were occasionally present. Repair is indicated for most pericardial tears to prevent herniation of the heart or abdominal viscera.