To investigate the likely source population and candidate vectors of Candidatus Rickettsia tarasevichiae, the prevalence of this bacteria was quantified in specimens of four tick species that mainly parasitize humans collected from 13 sites along the Chinese—Russian border. The presence of the bacteria was determined by detecting its specific citrate synthase (gltA) partial gene and outer membrane protein A (ompA) partial gene. Only Ixodes persulcatus Schulze was found to be naturally infected with C. R. tarasevichiae, which had an overall prevalence of 1.53% in both sexes. C. R. tarasevichiae is an emerging, tick-borne human pathogen and this finding may partially explain recent human cases of infection by this organism in China. Public health authorities should be aware of the potential risk posed by the transmission of this bacterium to humans by ticks.