A 3 month-old male dog with clinical signs of anorexia, soft stool, ocular and nasal discharge, cough and respiratory distress was submitted to the Cheju National University for diagnosis. At necropsy, tan to pulp]e-red sublobar to lobar consolidations were presented in apical and cardiac lobe of lung. Histopathologically, severe diffuse bronchointerstitial pneumonia with necrotic bronchiolitis was noted in the lung. The demyelinating encephalitis and astrocytosis were presented in cerebellum and cerebrum. Numerous round, ovoid or cluster of tachyzoites were also identified in alveolar lumen, alveolar wall and cytoplasm of macrophages in the lung. The orgasnisms were demonstrated as Toxoplasma (T) gondii by immunohistochemistry. Intranuclear or intracytoplasmic eosinophilic inclusion bodies were seen in the glial cells of the cerebellum. Canine distemper virus (CDV) specific antigens were demonstrated in the cerebellum by the immunohistochemistry. In our knowledge, this is believed to be the first confirmed report of co-infection of CDV and T gondii in dog in Korea.