The prevalence of rickettsiae, ehrlichiae, and the rickettsia-like endosymbiont called Montezuma relative to that of Borrelia was determined in questing Ixodes persulcatus (I. persulcatus) ticks collected in 2002-2003 from Vologda Province, Russia. Ehrlichia muris, Anaplasma phagocytophilum, Montezuma, and new spotted fever group rickettsiae were detected by polymerase chain reaction (PCR) for the first time in this area. The rickettsiae were all Candidatus Rickettsia tarasevichiae, the furthest west this organism has been detected. After Borrelia, Montezuma was the agent most frequently detected; it may be present throughout the distribution of I. persulcatus in Russia. Ehrlichiae and rickettsiae frequently share the same tick host with Borrelia burgdorferi sensu lato so cotransmission and mixed infections in vertebrate hosts, including humans, may occur.