Human lactoferrin contains 2 asparagine-linked sugar chains in 1 molecule. These sugar chains were released as oligosaccharides by hydrazinolysis from two lactoferrin samples of different races. The two oligosaccharide fractions gave exactly the same fractionation pattern upon paper electrophoresis and Bio-Gel P-4 column chromatography after sialidase digestion. A structural study of the oligosaccharides obtained from the two samples by sequential exoglycosidase digestion in combination with methylation analysis also gave the same results indicating that there is no racial difference both in quality and quantity of the sugar chain moiety of lactoferrin. In addition to the two acidic sugar chains, NeuAcα2→6Galβ1→4GlcNAcβ1→ 2Manα1→6(NeuAcα2→6Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4(Fucα1→6)GlcNAc and Galβ1→ 4(Fucαα1→ 3)GlcNAcβ1→ 2Manα1→ 6(NeuAca2→6Galβ1→4GlcNAcβ1→ 2Manα1→ 3)Manβ1→4GlcNAcβ1→4(Fucα1→3) GlcNac, and two novel acidic sugar chains, Galβ1→4(Fucα1→3)GlcNAcβ1→2Manα1→6(neuAcα2→6Galβ1→4GlcNAcβ1→3GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAβ1→4(Facα1→6)GlcNAc and Galβ1→4(Fucα1→3)GlcNAβ1→3Galβ1→4GlcNAcβ1→2Manα1→6(NeuAcα2→6Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4(Fucα1→6)GlcNAc, were found to occur in human lactoferrin.