Comparative Legal Analysis of the Forensic Examination of Explosive Substances, Explosive Devices, and Traces of Their Use Based on the Legislation of the Republic of Kazakhstan and the Russian Federation This paper presents a fundamental comparative legal analysis of the theoretical, procedural, and methodological foundations of the forensic examination of explosive substances and explosive devices within the legal systems of the Russian Federation and the Republic of Kazakhstan. The study is based on a detailed examination of criminal legislation, normative resolutions of supreme courts, and departmental instructions of the two states. Particular attention is paid to the divergence of law enforcement practice regarding the qualification of illicit trafficking in improvised explosive devices, the definition of criteria for the «fitness» of objects for explosion, and the delineation of competencies between state and private forensic experts. The paper details the algorithms for appointing and conducting explosive expertise, analyzes typical investigative errors, and proposes ways to unify expert methodologies within the framework of interstate cooperation. The relevance of the study is due to the need to harmonize approaches to combating transnational terrorism and illicit arms trafficking in the Eurasian space.