The commission of an act or action that is typically fatal is a determining factor in identifying the type of murder. The element of intent in this act, which is explained according to the second paragraph of the amended Article 290 in 2013, is considered as a criterion for proving premeditated murder. The criteria according to which a typically lethal act is identified originate from the origins of Islamic jurisprudence before the principles and criteria of modern criminology and the issues of attribution of punishment. However, some aspects of identifying whether an act is typically lethal in jurisprudential jurisprudence differ based on the opinions of jurists. Realizing the importance of such an issue, the present paper has studied this issue comparatively in the laws of Iran and Egypt. The results of this study show that the Egyptian legislator has been more strict in using a weapon than his Iranian counterpart and as the intention to use a weapon in Iran is to carry a typically lethal act, this Egypt is still a place for further reflection. has it. However, what needs to be reviewed in both legal systems is the fact that, for reasons and justifications, the mere use of a weapon can not be considered a typically deadly act.