A 6 yr old castrated male Clumber spaniel was referred for evaluation of acute paraplegia. MRI of the thoracolumbar spine demonstrated an intradural-extramedullary mass lesion at the level of T12 and extradural spinal cord compression at L1–L2. A hemilaminectomy was performed to achieve gross total resection of the mass lesion and removal of extruded disc material. A diagnosis of spinal choroid plexus tumor (CPT) and intervertebral disc extrusion was made. At 4 mo postoperatively, MRI demonstrated a mass lesion at the right lateral aperture of the fourth ventricle. Spinal drop metastasis from a primary intracranial CPT was suspected. The dog was ambulating independently and neurologically normal at that time. At 17 mo postoperatively, a third MRI was performed owing to decreased postural reactions in both hind limbs and vision loss in the right eye, and it demonstrated an increase in size of the intracranial mass lesion. These two additional MRI studies of the entire central nervous system showed no other metastatic lesions nor any evidence of local recurrence. At 25 mo postoperatively, the dog died at home. This is the first case report of surgical intervention and antemortem histopathological diagnosis of a spinal CPT in a dog.