Antibodies to Anaplasma phagocytophilum and Ehrlichia chaffeensis were detected by the immunofluorescent antibody (IFA) test in sera collected from cats, thoroughbred horses and Holstein cattle in Gwangju, Jeonju and Jeju Island of Korea. Two hundred fifty four sera (33 feral and pet cats, 92 grazing horses and 129 grazing cattle) were obtained from Republic of Korea. Antibodies to A. phagocytophilum (titer $geq$ 80) were detected in 6 of the 33 feral and pet cats (18.2%), and 1 seropositive cat (3.0%) also had antibodies to E. chaffeensis. Only 1 of 129 (0.8%) cattle and 2 of 92 (2.2%) horses had antibodies to A. phagocytophilum. Antibodies to E. chaffeensis were not detected in either of these animals. This is the first report of serological evidence of A. phagocytophilum and E. chaffeensis from cats, cattle and horses in Korea. These rickettsial agents could have an important impact on human health or impact animal health with economic losses among industrial grazing animals in Korea.