Background: Emergent and re-emergent canine tick-borne infections are attracting increasing attention worldwide. The rise in pet ownership and the close relationship between dogs and their owners are the most concerning factors because dogs may act as competent reservoirs for human tick-transmitted infectious agents. Objectives: This study contributes to the epidemiological surveillance of canine ticktransmitted infections with zoonotic risk in the Republic of Korea (ROK) by investigating the seroprevalence of the pathogens, Anaplasma spp., Borrelia burgdorferi, and Ehrlichia canis. Methods: Four hundred and thirty whole blood samples from domestic dogs were collected in seven metropolitan cities and nine provinces in the ROK and tested using SensPERT Ab test kits (VetAll Laboratories®) to detect seroreactive animals. Results: The seroprevalence rates identified were 9.8% (42/430) for Anaplasma spp., 2.8% (12/430) for B. burgdorferi, and 1.4% (6/430) for E. canis. The risk factors evaluated in this study that could be associated with the development of a humoral immune response, such as sex, age, and history of tick exposure, were similar. There was only one exception for dogs seroreactive to Anaplasma spp., where the risk factor “tick exposure” was statistically significant (p = 0.047). Conclusions This serological survey exhibited the widespread presence of Anaplasma spp., B.burgdorferi, and E. canis throughout the ROK. Hence, dogs may play a key role as the sentinel animals of multiple zoonotic infectious agents in the country.