Updated publication reference for PubMed record(s): 29981398. This study investigated proteome profile in the hippocampus, medial prefrontal cortex (mPFC), and striatum of 14, 18, 23, and 27 months old rats in order to see the effect of aging on proteins in these regions. Using ultrahigh performance liquid chromatography coupled with Q Exactive HF Orbitrap mass spectrometry, we identified 1074 proteins in the hippocampus, 871 proteins in the mPFC, and 241 proteins the striatum. Ninety-seven, 25, and 5 of these proteins were differentially expressed with age in the hippocampus, mPFC, and striatum, respectively. Overall, aging causes divergent protein changes in specific brain regions, with the most prominent changes observed in the late-aged.