We studied the relation between cerebral white matter damage and clinical data in nine patients with dentatorubropallidoluysian atrophy (DRPLA). All patients showed pseudo-Huntington form. The study produced five results. (1) The four of the nine patients showed diffuse hypodensity of the cerebral white matter on CT. We studied one of this four patients by MRI. The hypodensity area on CT showed marked high signal intensity by T2-weighted image on MRI. (2) The onset age was later in the patients with cerebral white matter damage as compared with the patients without this damage. (3) All patients showed subcortical dementia, which was more remarkable in the patient with white matter damage. This suggests the relation between cerebral white matter damage and progression rate of subcortical dementia in DRPLA. (4) Gait disturbance progressed more rapidly in the patients with cerebral white matter damage. (5) The homovanillic acid (HVA) and 5-hydroxyindole acetic acid (5-HIAA) concentration in CSF decreased more remarkably in the patients with white matter damage.