This work is presented as a constitutional analysis of the affectation suffered by the procedural subjects in a criminal case, when the states, in order to guarantee a criminal policy of repression, violate the universal principle of the presumption of innocence, through the recurrent application of preventive detention, a precautionary measure of a personal nature, considered a measure of last resort. Throughout the analysis certain questions are raised, which undoubtedly require dogmatically based answers, among others, is the constitutional principle of the presumption of innocence violated in Ecuador?