This article deals with a subject that in recent years has been part of the discourse of lawyers, judges and even politicians, we refer to the right to be tried within a reasonable time, although we prefer to call it “the right to have a trial concluded within a reasonable time”. But we will not be content with a historical-dogmatic presentation of this right, but will address the problem that we see in the development of trials: without a fixed time limit, the right to have a trial concluded within a reasonable time loses its validity and is sometimes illusory. Therefore, after analyzing the doctrinal proposals, such as the theory of no time limit -which has been adopted by international courts (European Court of Human Rights [ECtHR] and Inter-American Court of Human Rights [IACHR]), as well as the Constitutional Court and the Supreme Court of Peru- and the theory of the fixed time ...