The Republic of Guatemala has experienced the most important fact of its legal background, in the last decade of the 20th century. It started with a reform in the criminal justice system, which radically changed, the administration of justice, abandoning at the same time, the inquisitorial model (written trial) an adopting the accusatory system (oral trial). The reform of the criminal justice system of Guatemala, formally started the first of July of 1994, with the going into effect of the new law for the reform of the criminal justice system, which in fact is not over yet. This open the door for the reform of the criminal justice system in Latin America, which has to be seen in the global context, as the result of political and economical facts that have changed the sequence of human history, as have disappearance of the Berlin Wall, the end of the Cold War, the democratization of all countries of the area, the ever changing technological advances of the new society of knowledge and international globalization, that brought new criminal forms and social conflicts, which demand a rapid and transparent application of criminal justice, taking into consideration that it is fundamental in the construction of a democratic country, in the constitutional state of law. This is the central motivational factor of this doctoral thesis; basically contains an analysis of the criminal justice reform in Guatemala and a proposal that allows consolidation of this reform; considering the fact that the reform began twenty years ago, the real process that can guarantee an accurate implementation of the model, is currently in place, and everything else depends on the success or failure of the reform. This investigation is structured in six chapters; the first one explains the criminal justice reform in Guatemala and the second, the criminal justice reform in Latin America; the third one refers to the constitutional principles and guarantees of the criminal justice reform in Guatemala; the fourth, considers the main principles of the accusatory system; the fifth concerns the phases of the criminal justice reform in Guatemala and the sixth addresses the proposal for the implementation of the model, which is now been in progress, and the last chapter presents a conclusion, bibliography and a glossary. It is up to those of us, who in one way or another contribute, with the change, to demonstrate that the right application of the accusatory system in Guatemala, guaranties that the reform of criminal justice is the constitutional instrument to prove the guilt or innocence of the accused, and this should be primary objective of the criminal law. It is also the inspiration for this dissertation.