Between April 6 and July 20, 1994, after the plane crash carrying, among other passengers, the then president of Rwanda, Juvenal Habyarimana, one of the greatest genocides in contemporary history took place, the genocide in Rwanda. In an organized and systematic way, it is estimated that between 800,000 and 1,000,000 people, Tutsis in particular, were exterminated. Through Resolution number 955/94, the UN Security Council expressed concern about the serious violations of international humanitarian law that occurred in Rwanda. In this sense, the International Criminal Court of Rwanda (ICTR) was created, with a mandate to investigate the crimes committed during the genocide of that country and punish those responsible for these crimes. This study aims to verify the contributions of the ICTR to International Criminal Law and International Criminal Justice. It appears that the ICTR assisted in the definition and elaboration of several concepts on the central international crimes provided for in the ICTR Statute and in the 1948 Genocide Convention. Furthermore, it produced abundant jurisprudence and a large corpus of substantive and procedural law, and effected the accountability of the great leaders of the genocide in question. In this way, it contributed to the evolution of International Criminal Law and a creation of a permanent international criminal court.