Bacillus cereus is an opportunistic Gram-positive anaerobic spore-forming bacterium found in various environmental conditions. One of the pathogenicity factors is hemolytic toxin II, which belongs to the group of β-barrelpore-forming toxins. HlyII B. cereus differs from other β- barrel pore-forming toxins by having a C-terminal extensionof 94 amino acid residues. In this work, the binding sites of monoclonal antibodies obtained against recombinantHlyIICTD on the protein surface were determined. Using monoclonal antibodies, it was shown that HlyIICTD interactswith the erythrocyte membrane in a strictly defined manner. The localization of epitopes recognized by monoclonalantibodies suggested that the binding site of HlyIICTD with the membrane is localized in the C-terminal region ofHlyIICTD molecule.