Abstract: This article examines the concept of genocide from the point of view international legislation, its applicability to the mass violence phenomena known as Holocaust and Gulag, the difficulties of interpretation and the various solutions proposed by contemporary scholars. It seems that there is a need for a change in the definition of genocide in the international law, in the sense of updating this definition to the political and social developments in the world. The current concept of genocide, regulated by the UN Convention on the Prevention and Punishment of the Crime of Genocide poses a series of impediments that makes it difficult to be applied to the various situations of mass violence. Especially the omission of political and social groups from the protected categories by the UN Convention, together with the extremely rigid requirements of evidence ? such as proving the intent to destroy, in whole or in part, a group - make it a crime extremely difficult to prove in court. Genocide also overlaps with other crimes of international law and political science concepts ? such as crimes against humanity, ethnic cleansing, democide, politicide, ethnocide ? an aspect which needs to be clarified in a future clearer and less ideologized codification.