The relative differences between post-translational modifications (PTM) of proteins in blood plasma samples of patients with cerebral ischemia (CI) and healthy people were investigated on the basis of the method of comparative proteomic analysis without a label based on the technology of tandem HPLC - MS/MS. For the detection of PTM, we used multiple search MS / MS in the database Mascot installed variable PTM and Progenesis LS-MS software. In the CI plasma, we observed an increase in the share of posttranslation modified peptides. Such PTM proteins as phosphorylation of serine, threonine and tyrosine, acetylation of lysine and N-terminal protein, ubiquitination of lysine and deamidation of glutamine related to clinically significant processes were revealed.