An unusual form of cerebellocortical degeneration called cerebellar granuloprival degeneration was diagnosed in a four-month-old Chihuahua. The dog had a two-week history of progressive signs of cerebellar dysfunction, including a wide-based stance, intention tremors and bilateral absence of menace response without visual impairment. On MRI of the encephalon, a reduction in cerebellar size was detected. On histopathological examination, depletion of the cerebellar granule cell layer was observed, in addition to neuronal degeneration in the vestibular nuclei, reticular formation, red nucleus and internal laminae of the parietal and temporal cortices. A diagnosis of cerebellar granuloprival degeneration with trans-synaptic degeneration was made. To the authors’ knowledge, this is the first case report of cerebellar granuloprival degeneration in a Chihuahua and the first report of cerebellar granuloprival degeneration with trans-synaptic degeneration in a dog.