This research proposes to confront the decision of the Brazil’s Supreme Federal Court in the ADPF 153’s judgment with the subsequent and divergent sentence of the Inter-American Court of Human Rights handed down in the case Gomes Lund and others vs. Brazil, refered to the event known as Araguaia Guerrilla. Both decisions involve the theme of Brazil’s transitional justice and analyzed the extent and validity of the amnesty granted by Law 6.683/79 to human rights violations, occurred during the brazilian military regime. The results of these trials, however, were fundamentally opposite to each other. Brazil’s Supreme Federal Court, in April of 2010, declared the constitutionality and efficacy of the brazilian Amnesty Law, maintaining (and reaffirming) the official interpretation, tha lasts since 1979, that this law doesn’t allow the prosecution of ordinary crimes committed by agents of repression against civilians during the military regime. Afterwards and in a contrary way, the Inter-American Court of Human Rights, in November of 2010, expressly declared that the same law has no legal effects and blamed the brazilian State internationally, precisely because of its amnestied stance. The study starts demonstrating the legal linkage of the the brazilian State to the international legal apparatus of human rights, at the global and regional levels, and its submission to the Inter-American Court’s jurisdiction. Subsequently, it evidences the arguments used to support the oppositte deciosions of the SFC and the IACHR. Finally, it outlines an analysis about those two judgements and their consequences for the treatment of transitional justice in Brazil, considering its aspects of justice, truth, memory, reparation and institutional reforms.