Abstract: In this study, the jurisprudential and legal principles of Article 220 in the Islamic Penal Code (IPC), which is about the murder of a child by his/her father or father’s father are investigated. In that article, the term “father” refers to one’s biological father and not his/her stepfather. Even if the father is a Kafir (a person who does not believe in Islam or religions such as Christianity or Judaism) and has murdered his Moslem child, he has to be punished according to the IPC. What the word “child” means in the Code is one's biological child and not his adopted children and there is not any difference between minors and adults, sane children and insane ones and males and females. Since common jurisprudents consider birth as the basis for judgment, they think that regarding the meaning of parent, one's mother, mother's father and father's father should also be judged according to the same article. However, jurisprudents of the Imamyyah sect, believe that it is sufficient to consider what is explicitly stated in the text of the article. It must be stated that according to the customary truth and the jurisprudents consensus, one’s father’s father is the same as one’s father. The only exception that exists is killing one’s child in war. However, the father would be sentenced to death according to the laws of Islam regarding armed conflict and not based on the law of vengeance. When someone is murdered and the murderer claims to be his/her father, it is preferred to refer to the rules of vengeance. A second person’s cooperation with a father in murdering his child will not prevent the law from sentencing the partner to vengeance. A father’s order to murder his own child would not exempt the murderer from vengeance. When a father is addicted to infanticide an uncommon opinion holds that the father must be sentenced to vengeance. Since all the conditions of death retribution are also true about dismembering retribution, disproof of fatherhood is a condition.