Severe cardiac injury due to nonpenetrating blunt chest trauma is not uncommon, but survival to reach the hospital is rare. Successful management of fatal cardiac rupture depends on the high suspicion and on the prompt exploration. In the patient presented, the interatrial septal rupture was found associated with the right atrial rupture and the patient was successfully treated under the cardiopulmonary bypass. Although many types of cardiac rupture cases survived have been reported in the literature, we have been unable to find the interatrial septal rupture case like us. We would therefore like to report our experience with surgical repair of nonpenetrating rupture of right atrium and interatrial septum.