Infanticide represents the type of homicide that most expresses the cruelty of this crime, the characteristics of this fact demand an expertise of extreme quality due to the constant and rapid changes of traces and evidence useful for subsequent forensic determinations. When the violent death of the product of conception occurs, the medico-legal autopsy becomes the decisive procedure for the case to proceed or not with the accusation, the precision of being born alive is the key determination and at the same time the challenge for the forensic doctors, to specify if there was extrauterine life or not defines in many legislations the status of "person", this is the reason for serious debates that include the scientific, legal, social and religious field. The physical examination of the puérpera, the inspection of the place of the fact by the forensic experts even when the product of conception is in the same and the medico-legal autopsy are the three essential procedures. From the above analysis we propose a guide with practical theoretical elements to be taken into account in the medico-legal action for the investigation of this criminal typology, in addition to specifying the causes and circumstances that mediated in the fact.