Cardiac injury following blunt chest trauma is common in motor vehicle accidents due to a crush or blast injury. Severe cardiac trauma is associated with a very high mortality. If a cardiac injury develops several weeks after non-penetrating chest trauma, establishing a causal link between the traumatic event and the cardiac injury becomes complicated. This article reports a case of fatal delayed hemopericardium and hemothorax following a motor vehicle accident including blunt chest trauma 34 days prior to death. The cardiac injury was caused by displacement of a sharp irregular fragment of one of the decedents fractured ribs and the primary defect was sealed by blood clots. Subsequent bleeding occurred when the thrombus was displaced. Since the incidence of blunt high-energy chest injuries is relatively high, heart and large vessel injuries must be taken into account and a comprehensive examination needs to be done in order to prevent the delayed development of fatal complications.