A progressive neurological disease affecting twenty-two young adult dogs of smaller breeds is reported. The disease was most often acute in onset and the neurological signs included cervical pain, seizures, behavioural changes, ataxia, head tilt, muscle tremor and paresis. The lesions were those of a disseminated granulomatous meningoencephalomyelitis in which perivascular cuffs of macrophages and lymphoid cells were the predominant finding. Severe lesions were most often seen in the cerebral white matter although the brain stem, mid-brain and spinal cord were also commonly affected.