Mitochondrial DNA (mtDNA) variation was studied in population of Oroks (n = 61), the indigenous inhabitants of Eastern Siberia. Most of the mtDNA types examined fell into five haplogroups (C, D, G, M10, and Y) typical of Eastern Eurasian populations. For three haplogroups (D, C, and M10), the founder effect was established. In one individual, a unique lineage belonging to haplogroup HV and typical of Caucasoids was detected.