The diagnosis suicidal or homicidal stab injury of the heart affords a very close cooperation of the police and the forensic pathologist. In the first six months of 1988 the institut of forensic medicine of the MHH was obliged to four cases of isolated stab wound of the heart without other injuries with the question of suicidal action. The differentiation between suicide and homicide in two fatal cases was possible, considering as well autopsy results, as the facts found at the place of death and surrounding investigation results.