In this study, the authors evaluated the cerebral atrophy in 56 chronic hemodialyzed patients, who did not have clinical episodes or radiologic findings of cerebrovascular diseases, and 42 controls. Using computed tomography (CT) images, brain atrophy index (BAI), the proportion of subarachnoidal plus ventricular space in the cranial cavity, and ventricular area index (VAI), percent area of ventricle in the brain, were calculated. CT of the brain demonstrated an age-dependent increase in BAI in both hemodialyzed patients and controls. BAI and VAI were greater in hemodialyzed patients than healthy controls and the difference was significant at ages under 60 years in BAI and at ages less than 50 years in VAI. The atrophy of the frontal parts of the brain in patients on hemodialysis for 10 years or more was significantly greater than in patients dialyzed for less than 10 years. There was a significant negative correlation between BAI or VAI and hematocrit. These findings indicate that renal failure or hemodialysis itself might cause cerebral atrophy, and that the cerebral atrophy is more prominent in patients on hemodialysis for a long duration and with low hematocrit.