White matter changes in Alzheimer's disease patients were the subject of the study. One hundred and seventeen cases clinically diagnosed according to NINCDS-ADRDA criteria as probable Alzheimer's disease were assessed. In computer tomography two types of pathological changes were observed; the so called leucoaraiosis and the perivascular focal alterations. Leucoaraiosis appeared in 20% of cases and focal changes were visible only in 4 cases A significant correlation was found between the presence of leucoaraiosis and the age and the presence of coronary disease. Hypertension, diabetes and brain atrophy did not seem to influence the occurrence of white matter alterations of either type.