The purpose of the study was to identify key barriers preventing the effective application of generally accepted norms and principles of international law in criminal proceedings. The study was devoted to the analysis of the problems of the implementation of international standards in the national legislation of the Kyrgyz Republic and the Republic of Kazakhstan. The methodology included a comparative legal analysis of national legislation and a regulatory analysis of international standards in this area. The results of the study showed that, despite the formal recognition of international standards of criminal justice, their effective implementation in Kazakhstan and Kyrgyzstan faces several legal, institutional and sociopolitical challenges. Among the key barriers, legal gaps have been identified, allowing for variability in the interpretation of international law norms, which leads to their unsystematic and often selective application. In addition, insufficient harmonization of national legislation with international obligations was noted, especially regarding the protection of the rights of the accused, extradition, immunity of officials and respect for procedural guarantees. An analysis of the institutional framework revealed limited independence of the judiciary, high levels of corruption in law enforcement agencies and insufficient effectiveness of international cooperation mechanisms. Based on the identified problems, recommendations for improving the criminal justice system were proposed. In particular, the need to eliminate legal gaps and improve mechanisms for interpreting and adapting international norms in national legislation was substantiated. An important area of reform is related to ensuring the independence of the judicial system through the introduction of transparent mechanisms for the selection and rotation of judges, and strengthening responsibility for violations of procedural norms.