This paper examines an interpreter’s use of self-repairs as a coping strategy to address his lack of Russian proficiency. A discourse analysis was undertaken of a video recording (157-minutes in length) of a prosecutor’s interview of a suspect from a Russian-speaking background. Self-repairs, which refer to a speaker correcting their own utterances without external stimuli, occur when a speaker detects discrepancies with the communicative intention or a failure to meet the criteria of production (Schelgoff et al. 1977; Magnifico & Defrancq 2019). Adapting the self-repair categorizations proposed by Postma and Kolk (1993), LaSalle and Conture (1995) and Lee (2009), this study analyzed the interpreter’s self-repair attempts in interpreting and tallied the frequencies of different types of self-repair. The results showed that the untrained interpreter’s self-repairs were essential to the interpreter-mediated communication, particularly because of his limited interpreting competence. His self-repair attempts, which were numerous and frequent, do not reflect those displayed by professional interpreters’ and indeed are closer to those displayed by language learners. The analysis further revealed that the interpreter’s self-repairs differed depending on the directionality of his interpreting in terms of frequency and purposes. The findings also showed that despite numerous self-repairs, the communication problems that arose in the interview were not successfully resolved due to the interpreter’s lack of interpreting skills, including his low-level language proficiency. The findings emphasize the importance of engaging competent interpreters when interviewing suspects from non-Korean speaking backgrounds.