A case of interventricular septal defect secondary to blunt chest trauma is reported. It was characterized by a disconnection of the interventricular muscolar septal in the anterosuperior part of the heart wall. The diagnosis, suspected by clinical and instrumental parameters, was definitely confirmedy by hemodynamic and contrastographic examination. Repair surgery of the defect with a dacron patch was performed, using extracorporea normothermic circulation seven months after the accident. The patient was examined three months and twelve months after the operation; the clinical examinations did not reveal any cardiac murmur and the patient's health was satisfactory. The incidence, mechanism of rupture of interventricular septum and the main surgical and clinical aspects of this type of pathology are discussed.