Two decades ago, Chile took action and started a process that modified its entire criminal system, a process that did not commence in Chile alone, but in the majority of South American countries who followed the same path; in Chile, the adversarial system was gradually implemented, and since 2005 it remains in force in every part of the country. Perhaps, the most important objective and/or effect that this change brought to the Chile’s criminal law was to ensure the complete respect towards the fundamental rights of those who were under investigation in the criminal system, overcoming the problems and obstacles that the previous inquisitorial system presented. Thereby, one of the aspects that this new criminal system improved was granting the authority to judges to issue a preventive detention as a personal preventive measure during the aftermath of the criminal process, whilst such measure was applied in a massive and general manner within the previous system. This article aims to present the main impacts that the application of this new system of criminal procedure has introduced in Chile, regarding the use of the preventive detention as a personal preventive measure during the development of the criminal processes. The author intends to examine whether the overhaul of the criminal procedure system in Chile has been a useful tool to streamline the use of the preventive detention measure in the criminal process, namely, if such change has been able to create a conduct consistent with the internationally recognized values and that should guide the use of this preventive measure, especially regarding its exceptional nature and the right to be considered innocent before trial. To comply with the previously stated purpose, this article is divided into two sections. The first one, beyond analysing the context of the preventive detention during the Chilean inquisitive system in the scope of the changes at a normative level that the new criminal procedure system proposes, is also used as a baseline for contrasting the outcomes obtained after implementation of these changes. The second section is dedicated to analysing the impact of the overhaul of the criminal procedure system with regard to applying the preventive detention in Chile and the series of changes that have been implemented.