The article provides a comparative analysis of legal acts regulating the organization of forensic activities, as well as the legal status of knowledgeable persons in criminal proceedings in Russia and Latvia. Comparative legal analysis of normative acts consists in comparing the prescriptions of legal norms, legislative terms and definitions, allowing one to see the general and special, typical and unique in the regulation of forensic activities, as well as the rights and obligations, the volume and nature of the procedural functions of knowledgeable persons in criminal proceedings Russia and Latvia. The study is carried out on the basis of a comprehensive comparative legal analysis of the latest editions of criminal procedure laws (codes), laws in the field of organizing forensic activities in Russia and Latvia, by-laws, as well as other primary sources, including foreign ones, in the original language. Knowledgeable persons, i.e. persons applying special knowledge in criminal proceedings in Russia, are experts and specialists, in Latvia – experts, auditors and specialists. The legal status of knowledgeable persons in criminal proceedings in Russia and Latvia is largely comparable, but not identical. And, despite the transformation of the criminal procedural legislation of Latvia, in accordance with international legal norms and standards of the European Union, the provision of Soviet law on the use by knowledgeable persons of special knowledge in legal proceedings was preserved in the Latvian criminal process. The Code of Criminal Procedure of Russia classifies an expert and a specialist as other participants in criminal proceedings, that is, persons performing the function of promoting justice. Whereas the Latvian Criminal Procedure Law refers an expert and an auditor to persons having powers in criminal proceedings, a specialist – to other persons involved in criminal proceedings. And, if the expert and the auditor in the Criminal Procedure Law of Latvia are considered as independent participants in the criminal process, then the role of a specialist in legal proceedings is reduced to the level of “auxiliary personnel”. An expert and an auditor, according to the requirements of the Criminal Procedure Law of Latvia, are involved in criminal proceedings to give an opinion and fulfill the obligation to provide evidence, that is, as “means of ensuring judicial evidence”. Specialist – to assist officials performing procedural actions in fixing the progress and results of their conduct, using technical means to identify circumstances relevant to the case, but without conducting practical research in search of traces of a criminal act. The results of the comparative legal analysis of the normative acts regulating the rights, obligations, scope and nature of the procedural functions of knowledgeable persons in the criminal proceedings of Russia and Latvia allow us to expand our understanding of the application of special knowledge in the criminal proceedings of foreign states, as well as to critically assess the national criminal procedure legislation for the purpose of its further improvement and optimization. Based on the results of the study of the normative acts of Russia and Latvia, certain problematic aspects of the legal regulation of the procedural status of knowledgeable persons in the Russian criminal procedure legislation is noted, and generalizing conclusions are made.