The purpose of this study was an attempt to theoretically understand the subject of judicial consideration of complaints against decisions, actions (inaction) of officials carrying out criminal prosecution. The research was carried out on the basis of comparative legal, formal logical, empirical, statistical methods. Judicial statistics for the year 2020 have been provided, and legislation has been studied from a historical and contemporary perspective, taking into account the practice of the Constitutional Court of the Russian Federation. The problem is that, in practice, for about 20 years the courts have had difficulties in determining the subject of complaints, since neither in theory nor in practice a consensus has been developed on this issue. The Criminal Procedure Code of the Russian Federation also does not contain a definition of the concept of «subject matter». The situation is aggravated by the presence of evaluative concepts in the text of the law, leading to a varied understanding of the subject of appeal by the courts, which leads to a violation of the constitutional rights of citizens at the pre-trial stages of criminal proceedings. In the article, taking into account the analysis of the practice of the Constitutional Court of the Russian Federation, legislation and the opinion of scientists, a recommendation was made to amend the Criminal Procedure Code of the Russian Federation to specify the subject of consideration of complaints in accordance with Art. 125 of the Criminal Procedure Code of the Russian Federation in order to eliminate existing contradictions in practice and increase the level of protection of individual rights in pre-trial proceedings.