It is important that the judges abide by the constitutional and legal provisions on an adequate motivation and foundation of the sentences, enunciate the norms or principles that govern the legal argumentation and the principles of reasonableness, logic and understandability established by the Constitutional Court of Ecuador. It is of transcendence and importance of due process, since in light of the constitutional state of rights and justice; provides legal certainty. The work has been motivated by the publication of the work "Current approach to the motivation of sentences" by Gastón Fernando Valenzuela Pirotto 2020; problems of our community and the legal society; The objective of legally analyzing compliance with the principle of motivation was fulfilled, as a guarantee of due process in the issuance of orders by the Judges of the Penal Unit of the Santo Domingo Canton, to order preventive detention. The investigation analyzed records and sentences, a mixed approach was carried out, its methods used have been exegetical, deductive and analytical - synthetic, having a documentary-bibliographical and field character with the purpose of collecting expert criteria in constitutional law. and criminal procedural law, with the execution of semi-structured interviews, as well as to analyze judicial files on preventive detention in the Criminal Judicial Unit of Santo Domingo.