A 4-year-old female Shunauzer dog was referred to the Veterinary Teaching Hospital of Chungbuk National University due to anorexia and depression. The dog had a history of regular walking on grass fields, weight loss, and hyperthermia $(40.6^{circ}C)$. In the physical examination, lymph node enlargement was confirmed. Complete blood count result revealed leukocytosis and thrombocytopenia but there was no decreasing of red blood cells. On blood chemistry, serum ALP, GGT, CPK, and LDH were elevated. Abdominal radiograph showed splenomegaly. Anaplasma platys infection was suspected with inclusion body-like substances in platelets on blood smear. Anaplasma platys was confirmed by PCR. On the basis of laboratory examination, final diagnosis was anaplasmosis. Treatment was followed for 3 months with tetracycline and doxycycline. The patient was monitored every week during the treatment. The patient has recovered to normal condition without any clinical signs. We are going to emphasize the need of PCR technique in diagnosis and to report the possibility of long term treatment more than two months in rickettial disease.