The present paper studies the superior’s responsibility by war crimes according to the International law. After the revision of some aspects focused on its nature as responsibility by omission, its three constitutive elements are extensively examined. In general terms, these are: a) the existence of a superior-subordinate relationship; b) superior’s knowledge with regard to the war crimes committed by his/ her subordinates (mental element) and, c) that the superior does not fulfill his/her duties to prevent and punish the war crimes committed by his/her subordinates. The analysis of the International Criminal Court Statute and conventional norms of the International humanitarian law as well the jurisprudence of the International Criminal Tribunals for the former Yugoslavia and Rwanda are the main sources in order to study this important International law’s institution.