Antigens of infectious agents share amino acid sequences with human proteins. Such a peptide matching may lead to autoimmunity through crossreactivity phenomena following pathogen infection and/or immunotherapeutic approaches. In this framework, we analyzed as a model the primary sequence of human cytomegalovirus (HCMV) glycoprotein B (gB) protein and searched for viral peptide sequences shared with human proteins. We show that the HCMV antigen has a high peptide identity with a large number of human proteins at the penta-, hexa-, and heptapeptide level, with the viral versus human peptide overlap involving host proteins implicated in crucial processes such as embryonic development, spermatogenesis, spatial learning, and hippocampal plasticity, inter alia. This study might help understand the etiology of the pathologic sequela associated with HCMV (re)activation and, in addition, address scientific and clinical research toward the definition of antiviral therapeutics based on non-crossreactive viral sequences.