White matter low attenuation (WMLA) was seen on CT in 19.7% of 61 patients with probable Alzheimer's disease. Presence of WMLA was associated with higher age, more severe degree of dementia, and increased CSF/serum albumin ratio, but not with cardiovascular disorders. WMLA on CT might be related to minor vascular events, or Alzheimer patients with WMLA could even constitute their own subtype.