A 3-year-old castrated male Yorkshire terrier was referred to the Veterinary Medical Teaching Hospital of Chungnam National University. The owner complained the history of seizure before one month. barking at night, wheezing with continuous chewing motion while breathing, recent decreases of vision and weight loss. Computed tomography revealed hypodense areas in the brain and ventriculomegaly, Multifocal lesions were noted in magnetic resonance images, which were hypointense in T1-weighted images and hyperintense in T2-weighted images. Ventriculomegaly and intracranial arachnoid cyst were also observed. Finally, it was diagnosed as necrotizing meningoencephalitis by histopathologic examination after necropsy.