To characterize the neurophysiological profile of patients with Subcortical Vascular Encephalopathy (SVE) we compared the quantified electroencephalogram (qEEG) of 15 consecutive patients, demented and non-demented, with leukoaraiosis and multiple lacunar infarcts on tomographic scan and magnetic resonance investigation, with those of 30 patients with Alzheimer’s disease (AD) and 30 controls. The investigation was carried out using an EEG fast Fourier transform program, and the data obtained were transformed into mean frequency (MF), calculated in the left occipital derivation, and in percent difference (PD), calculated in eight derivations. The data obtained were compared with the scores of the mini-mental state examination (MMS). The results demonstrate that the patients with SVE displayed a different qEEG pattern in comparison with AD patients and controls, with a prevalence of EEG slowing in frontal derivations, and with good correlation between PD values and MMS scores. The qEEG may detect subtle and/or early changes in patients with SVE. The use of adequate spectral parameters may give valuable data for a better classification of dementia syndromes.