Abstract
This article analyzes wheter agreements are the suitable elements to guarantee the defendants’ rights in the accusatorial criminal procedure, for whose purpose it must start from the legal system and the criminal process location as part of it, that is, from a historical and comparative context. The analysis shows that the agreements are an anticipated sentencing form of the process that contributes to the effectiveness and efficiency of the system, but they do not materialize the own guarantees of the accusatory criminal system. The judge cannot get complete certainty beyond any reasonable doubt, that the factual, legal and evidentiary assumptions could be legal and do not tend to vitiate the criminal action by nullity.