Genetic constructs containing the human lactoferrin (hLf) gene were created within a joint program of Russian and Belorussian scientists. Using these constructs, transgenic mice were bred (the maximum hLf concentration in their milk was 160 g/L), and transgenic goats were also generated (up to 10 g/L hLf in their milk). Experimental goatherds that produced hLf in their milk were also bred, and the recombinant hLf was found to be identical to the natural protein in its physical and chemical properties. These properties included electrophoretic mobility, isoelectric point, recognition by polyclonal and monoclonal antibodies, circular dichroic spectra, interaction with natural ligands (DNA, lipopolysaccharides, and heparin), the binding of iron ions, the sequence of the 7 terminal amino acids, and its biological activity. The latter was assessed by the agglutination of Micrococcus luteus protoplasts, bactericidal activity against Escherichia coli and Listeria monocytogenes , and fungicidal activity against Candida albicans . We also demonstrated a significant increase in the activity of antibiotics when used in combination with Lf.