Aim. Confirmation of taxonomic position of Lactobacillus fermentum 90 TC-4 strain using phenotypic (classic microbiological, MALDI TOF mass-spectrometry) and genetic (16S rRNA gene segment sequencing and full genome sequencing) methods. Materials and methods. Object of the study - Lactobacillus fermentum 90 TC-4 strains from various collections. Mass-spectrometric analysis was carried out using Autoflex MALDI TOF mass-spectrometer (Bruker Daltonics, Germany), study of biochemical properties of the strain was carried out using API 50 CHL strips (Biomerueux, France), “DNA-sorb B” kit was used for isolation ofgenome DNA (CRIE, Moscow). Sequencing of the accumulated fragments of 16S rRNA gene was carried out using GenomeLab GeXP sequencing (Beckman Coulter, USA), full genome sequencing was carried out in MiSeq platform (Illumina). Assembly ofgenome and bioinformation analysis was carried out using BLAST program (www.blast.ncbi.nlm.nih.gov/blast.cgi), «CLC Bio Assembly» and genome server RAST (rast.nmpdr.org). Results. L. fermentum 90 TC-4 strain was established to be contaminated by L. plantarum culture in a series of cases. As a result of identification of a pure culture of L. fermentum 90 TC-4 strain using a specter of high-technology methods, membership of the strain in L. fermentum species has been proven. Conclusion. Taxonomic status of L. fermentum 90 TC-4 strain was confirmed.