Antibodies to the bovine prion protein were produced by immunizing mice of three lines with five synthetic fragments of the protein and six of their analogues. The analogues contained amino acid substitutions that, according to theoretical calculation, should lead to an increase in the immunogenic activity of peptides. All the peptides except for one induced the formation of antibodies. All the sera containing the antipeptide antibodies were tested by an immunohistochemical method. The sera effectively bound to brain preparations from an animal with spongiform encephalopathy were identified; it was shown that they do not interact with preparations of normal brain. Therefore, it was shown that the immunization of mice with synthetic fragments of a prion protein allows one to obtain specific antibodies suitable for the study and diagnostics of prion diseases.