Interventricular septum rupture following blunt chest trauma is a rare cardiac injury that sometimes is difficult to diagnose. It has a high mortality rate, especially when in cases of hemodynamic instability requiring early surgical repair. We report the case of an 18-year old man who suffered blunt thoracoabdominal trauma and hemorrhagic shock who required emergency abdominal surgery on three occasions. He was diagnosed of traumatic rupture of interventricular septum that had not been detected in the initial echocardiography, but was suspected after the right heart catheterism. Urgent cardiac surgery was performed 72 hours later because of hemodynamic instability.