Unlike their counterparts in budding yeast Saccharomyces cerevisiae, the glycoproteins of Schizosaccharomyces pombe contain, in addition to alpha-d-mannose (Man), a large number of alpha-d-galactose (Gal) residues. In both yeasts, large outer chains are attached to the oligosaccharide cores of glycoproteins during export via Golgi. Formation of the yeast-specific large outer chain is initiated by alpha-1,6-mannosylatransferase encoded by the och1 (+) gene, the disruption of which blocked outer chain elongation. We previously reported that N-linked oligosaccharide structures of S. pombe och1 Delta mutant consisted of Gal(2-6)Man(9)GlcNAc(2) with alpha-linked Gal residues attached to the core oligosaccharide moiety. The disruption of gms1 (+), a gene encoding the UDP-galactose transporter required for the synthesis of galactomannan, abolished cell surface galactosylation in S. pombe. In this study, we constructed a gms1 Delta och1 Delta double mutant and determined the N- and O-linked oligosaccharide structures present on the cell surface. Oligosaccharides were liberated from glycoproteins by hydrazinolysis and labeled with the fluorophore, 2-aminopyridine. The pyridylaminated N-linked oligosaccharides were analyzed by high-performance liquid chromatography in combination with alpha 1,2-mannosidase digestion and partial acetolysis. These analyses revealed that the N-linked oligosaccharides of gms1 Delta och1 Delta cells consisted of alpha 1,2-linked Man-extended core oligosaccharides (Man(8-12)GlcNAc(2)) from which the fission yeast-specific alpha-linked Gal residues were completely absent.