Abstract Domestic reindeer in Russia are a valuable resource of vital importance to the physical and cultural survival of the Northern indigenous minority. During the last decades, the mitochondrial (mt) genetic markers have been widely used as a molecular tool to investigate genetic structure and diversity of livestock species. Here we aimed at the assessing the mtDNA diversity of the domestic reindeer inhabiting the area from the Kola Peninsula in the west to the Chukotka region in the east. A complete cytochrome b (cytb) sequences (1,140 bp) from representatives of six populations, including Nenets (NEN, n = 16), Evenk (EVK, n = 12), Even (EVN, n = 6), Chukotka (CHU, n = 6), Chukotka-Khargin (CHUKH, n = 6) and Tuva (TUVA, n = 6) were obtained. Sequences’ alignment was conducted using MUSCLE algorithm in R package msa. In total, 34 haplotypes were identified. Median-joining network, constructed in PopART 1.7, revealed three major groups of haplotypes: the first one joined the samples of all the populations, the second one included NEN, EVN and CHUKH, and the third group was presented by the one sample of CHU. AMOVA, calculated in Arlequin 3.5.2.2, showed that only 9.58% of molecular variance could be explained by the differences between populations and 90.42% - within populations. Genetic diversity parameters calculated in DnaSP 6.12.03, demonstrated that average number of nucleotide differences (K) was highest in CHUKH (28.333) and EVN (27.409) and lowest in TUVA (4.533) and EVK (5.400). Nucleotide diversity (Pi) was 0.01238±0.00559, 0.00474±0.00091, 0.02404±0.00453, 0.01281±0.00464, 0.02485±0.00744, and 0.00398±0.00110 for NEN, EVK, EVN, CHU, CHUKH and TUVA, respectively. Our study demonstrated the lack of clear genetic structure of the studied reindeer populations in relation to cytb sequence. The level of genetic diversity was associated with census size and was lowest in the smallest Tuva population. This study was supported by RSF-21-16-00071 and Russian Ministry of Science and Higher Education-0445-2019-0024.