1. Although volumetric Magnetic Resonance Imaging (MRI) studies suggest regional cortical atrophy in Alzheimer's disease (AD), only one prior study documented atrophy of the parietal and insular cortex (Foundas et al, 1993). 2. To further investigate this potential early marker of AD, the authors computed volumetric measures of these regions on conventional axial MRI sections in 25 patients with mild to moderate "probable AD" and 25 age- and sex-matched controls. 3. Regions of interest (ROIs) from T1-axial images (5mm) were scanned into a PCX format (400 dots/inch) and volumes of CSF fluid were calculated using an Autocad program. 4. AD patients showed significant parietal (p < .01) and insular (p < .002) atrophy as compared to controls. 5. These findings suggest that atrophy of the parietal and insular cortex may occur early in AD patients, and that certain quantitative measures on conventional MRI accurately discriminate AD patients from controls.