The spread of the phenomenon of Holocaust denial, which has a strong discriminatory nature has led the international community to deal with the identification of limits on the freedom of expression in cases in which opinions are disseminated to deny the existence of crimes against humanity such as the Holocaust, established without any doubt on the historical level, also thanks to international and domestic courts. Both on the international and on the internal legal systems documents were adopted prohibiting the absolute denial of historical facts with regard to knowledge established beyond any doubt, limiting, in these cases, the right to freedom of expression. Such prohibitions were examined by the European Court of Human Rights that in several judgments has considered in accordance with Article 10 of the Human Rights Convention the punishment on domestic level of the perpetrators of theses denying the Holocaust, evaluating those views as religious and racial discrimination. Accordingly, the Court held that the denial of clearly established facts such as the Holocaust should be removed from the protection of Article 10, also thanks to Article 17 (Prohibition of abuse of rights). The Court on several occasions has considered the statements in which are supported denial of the existence of crimes against the Holocaust particularly serious and has applied to Article 17 to ensure the system and the values expressed in the Convention. Therefore, in the light of ECHR case-law it can be maintained that the Holocaust denial theories do not fall within the scope ratione materiae of the Convention as contrary to the fundamental values of democracy and of the Convention, as expressed in its preambular, namely justice and peace.