Human head and body lice host the obligate endosymbiotic bacterium "Candidatus Riesia pediculicola." In this announcement, we describe the complete ge-nome sequence of a "Ca. Riesia pediculicola" strain isolated from the human head louse, Pediculus humanus subsp. capitis. The inter-and intraspecific variations of endosymbiont genomes were investigated, and this strain was found to display high-level variations in its genome.