Based on an analysis of the polymorphism of nucleotide sequences (n = 111) of the control region (left domain) of mtDNA, the genetic diversity of the largest population of wild reindeer Rangifer tarandus in Eurasia, which inhabits Taimyr peninsula, was studied. High levels of gaplotypic (H) and nucleotide (pi) diversity (0.987 and 0.018, respectively) were revealed, which indicate the long existence of this population and the sufficiently stable growth of the population. The absence of long periods of abrupt decrease in the number of the Taimyr population of wild reindeer and/or facts of formation of its genetic diversity as a result of mixing of genetically distant conspecific populations is supported by the data on the distribution pattern of frequencies of pair differences between nucleotide sequences and the topology of the phylogenetic tree. The low level of genetic differences between reindeer from the western, central, and eastern groups reflects their common origin and close kinship.