To investigate metabolic changes in Alzheimer's disease (AD), we performed proton MR spectroscopy at 3T Spectra were acquired from the gray matter of the posterior cingulate gyrus and the precuneus, and from the parietooccipital white matter in nine AD patients and 12 controls. In patients, the N-acetyl group (NA)/creatine + phosphocreatine (Cr) ratios were decreased in both regions, and a decrease in the glutamate + glutamine (Glx)/Cr ratio and a correlation between the NA/Cr and Glx/Cr ratios were detected in the gray matter, but not in the white matter. These results suggest that NA and Glx metabolism are simultaneously affected in AD, however, metabolic changes in Glx are more profound in the gray matter than in the white matter.