DNA sequencing analysis of the mitochondrial DNA cytochrome oxidase H (COII) region was used to examine genetic variation in the termite genus Reticulitermes Holmgren. We examined 21 species and subspecies from three continents. Sequencing of a 677-bp region of a 780-bp amplicon from 41 individuals and from 17 sequences obtained from GenBank revealed 221 polymorphic sites within the genus. Tajima-Nei distances from species ranged from 0.9 to 12.7%, and parsimony and maximum likelihood analysis revealed several clades within the genus. Reticulitermes flavipes (Kollar) formed a distinct clade along with R. santonensis De Feytaud. European R. lucifugus (Rossi) formed a distinct clade with R. banyulensis (Beziers). Turkish R. lucifugus was distinct relative to European R. lucifugus, and along with R. clypeatus Lash from Israel formed a sister group with R. balkanensis Clement from Greece. This study provides support for the separation of Turkish R. lucifugus from European members of the species. This mitochondrial DNA marker was also able to identify several Reticulitermes specimens from Oklahoma, Texas, Missouri, and South Korea to R. flavipes, R. hageni Banks, R. virginicus (Banks), and R. speratus Shimizu.