Two judicial autopsy cases of sudden unexpected natural death were reported. In both cases it was suspected that the victims had died of a traffic accident or violent injury. It became clear, however, that both the cause of death had been myocardial infarction by the forensic autopsies and that the suspects had not been criminally responsible for the death of the victims. It is expected that sudden unexpected natural death whose cause and manner are unclear at first may occur more frequently following the increase of the number of death from ischemic heart disease in the future. In these circumstances the forensic autopsy of such cases will become more important socially.