Ovomucoid isolated from egg white of japanese quail contained mannose, galactose, glucosamine, and sialic acid (8.6 : 1.3 : 6.6 : 0.5 mol/mol) as sugar components. Sugar chains were liberated from the polypeptide portion by hydrazinolysis, N-acetylated and fractionated on Bio-Gel P-2. The reducing ends of the thus obtained sugar moieties were pyridylaminated. Chemical and exoglycosidase digestion studies of the fluorescent pyridylamino derivative of a major sugar fraction indicated the following structure for one of the major sugar chains of japanese quail ovomucoid; Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4GlcNAc.