Intraspecific variation in mitochondrial DNA of North American cervids was assessed with restriction enzymes to determine relationships among populations and subspecies. No variation was detected in moose (Alces alces) and little in elk (Cervus elaphus). Caribou (Rangifer tarandus), white-tailed deer (Odocoileus virginianus), and mule deer (Odocoileus hemionus) possessed considerable variation. Characteristic genotypes exist in caribou and white-tailed deer from different geographic areas although subspecies are not discernable as distinct mtDNA assemblages. Except for O. hemionus, intraspecific mtDNA sequence divergences are small (<2%). Subspecies of mule deer have divergent mtDNA (7%) and are the only subspecies of cervids with distinct genotypes.