Twenty-five patients were included in this study {Alzheimer disease (10 cases), MCI (15 cases)} and 15 healthy elderly controls. Mean MMSE scores were significantly lower in patients with Alzheimer’s disease compared with MCI and control cases (P < 0.001). Positive correlation (except left caudate nucleus) between gray matter volume reduction in MCI and AD in relation to elderly control and MMSE score was observed. The Auditory Verbal Learning Test (AVTOT) was significantly lower in patients with Alzheimer’s disease compared with MCI and control cases (P < 0.001). No significant differences were found between groups as regards age, sex, education or dominant hand. Significant gray matter volume reductions were found in both AD and MCI compared to healthy elderly control however no significant differences were found among MCI patients or AD patients. Sensitivity, specificity, PPV and NPV of caudate nucleus and hippocampal volume reduction in AD and MCI in relation to elderly control were higher than entorhinal cortex.