Abstract: 1. The amino acid sequences of bikazins (the double-headed Kazal-type proteinase inhibitors from submandibular glands) isolated from the snow leopard (Unica unica), the European mink (Mustela lutreola), and the European pine marten (Martes martes) were determined. 2. N-terminal domains of bikazins are characterized by a cysteine residue spacing that differs from that of C-terminal domains of bikazins and other Kazal-type proteinase inhibitor domains. 3. N-terminal sequences of bikazins seem to be specific for, and highly conserved within, each Carnivora family.