Introduction. Detention is the most restrictive preventive-imposed measure. Consequently, it is subject to careful legal regulation. The aim of this regulation is to prevent any ambiguity in the interpretation of criminal procedure rules, and inconsistent judicial practice regarding its selection and application. The present article explores certain issues of the selection and application of detention in pre-trial proceedings during criminal investigations, particularly in the context of inquiry, as well as in relation to the accused (suspects) who possess immunity from criminal prosecution. The issue of the necessity to enhance the criminal procedural norms governing the procedure of imposing this preventive measure on minors has come to the forefront due to recent amendments to Article 108 Criminal Procedure Code of the Russian Federation (hereinafter the CPC RF). Methods. General scientific methods of cognition, such as analysis, deduction, analogy, the systemic-structural method, as well as private scientific methods: the formal-legal and comparative-legal methods were used in this study. The results. The results of the study laid the groundwork for recommendations to revise and amend the explanations issued by the Plenum of the Supreme Court of the Russian Federation concerning the determination of the detention period for suspects whose criminal cases are in the form of inquiry. In addition, a proposal was made for the resolution of the legal dispute concerning the procedure for the imposition of detention on persons who are immune from criminal prosecution. In response to recent amendments to the Article 108 Criminal Procedure Code of the Russian Federation, a list of exceptional cases that are taken into account by the court when determining the detention of minors who have committed crimes of medium gravity has been developed. It has been conclusively determined that the complete substitution of this preventive measure with alternative measures is not feasible.