The paper is aimed at investigating the basic legal principles of interpreter's participation in the criminal proceedings in the Russian Federation. The topic under consideration is relevant due to the massive migration processes sweeping most European countries and Russia. Statistics show that in 2017 about 41,147 crimes were committed by foreign citizens in the territory of the Russian Federation. More recent survey shows that resident aliens committed approximately 10,415 criminal offenses, from January to March 2018. Very often offenders do not speak Russian, and therefore, the statistics of criminal offenses involving stateless persons and foreign citizens is only growing. Most of the above-mentioned individuals do not understand the language of legal proceedings and cannot participate in it on their own. The legislation of the Russian Federation provides for an interpreter who can supply them with qualified and professional assistance. Similar provision is envisaged in regulations of most of the Western and Asian countries, and though all of them are guided by the international rules, the national laws vary in many ways. Russian laws regulate this sphere in terms of rights, obligations and proceedings that are to be observed at different stages of investigating, court hearing and post-trial stages of criminal cases demanding professional assistance of interpreter and/or translator. The research methods involve theoretical and practical approaches, comparative analysis of relative rules in western countries and classification, description and other methods of reasoning allowing to reach objective results and conclusion. The practical relevance of the work rests in outlining pitfalls in laws concerning engagement of an interpreter into criminal proceedings in Russia. The output of the research can also be of certain value to professionals involved in court interpreting and government policies in this sphere and scholars interested in the topic.