This article examines the problematic aspects that arise during the investigation of war crimes, focusing on identifying the main challenges and developing recommendations to overcome them. It analyzes the difficulties faced by investigative bodies in collecting evidence, the legal and procedural barriers that complicate the investigation and prosecution of perpetrators. Special attention is given to the role of international law and the cooperation of interstate organizations in improving the effectiveness of investigations. As a result of the research, specific recommendations are proposed to enhance the quality of war crime investigations and strengthen the rule of law at the international level. The research on this topic analyzes the works of scholars such as I. Hlovyuk, V. Zavtur, N. Lashchuk, V. Navrotskaya, M. Pashkovsky, R. Serkevich, N. Ustritskaya, and others. Greater attention is paid to current legislative acts and the Rome Statute of the International Criminal Court. The issue of exchanging prisoners of war in Ukraine is regulated by various normative legal acts, including the ICC RS and the Criminal Procedure Code of Ukraine (CPCU). The appendix to Article 3 of the CPCU establishes that a person who has the procedural status of a suspect, accused, or convicted can be exchanged as a prisoner of war. Amendments to the CPCU regarding the interrogation of persons for whom a decision on exchange has been made do not contain substantive additions or clarifications, which may lead to inappropriate application of these provisions. Although the CPCU does not contain a separate norm regarding the procedural status of prisoners of war, the legislator has made changes to regulate the exchange of persons during martial law, which became possible thanks to the law dated July 28, 2022. Despite the legislator’s attempts to improve the procedure for exchanging prisoners of war, some aspects remain complex, which may violate the principle of legality and the rule of law. Ukraine, even without being a state party to the ICC RS, is obliged to cooperate with this international body in accordance with Article 12(3) of this statute. The presence of implementing legislation that regulates national cooperation procedures is a prerequisite for the comprehensive fulfilment of Ukraine’s obligations to the ICC. Better definition of the statuses of participants in criminal proceedings, particularly those for whom the ICC’s request for co-operation has been received, as well as the regulatory establishment of the status of prisoners of war, is needed. Ukrainian prosecutors and pre-trial investigation bodies should adhere to the specifics provided by the ICC Rules of Evidence when conducting interrogations of witnesses, suspects, and victims. Failure to take appropriate actions during interrogations may lead to the recognition of interrogation protocols as inadmissible evidence, which will reduce the number of high-quality evidence on the part of the prosecution.