The extracellular domain of E2 glycoprotein outer surface of the classical swine fever virus was expressed in epithelial kidney pig cells. The N-glycosylation determined by combination of Normal Phase-HPLC, Weak Anion Exchange-HPLC, exoglycosidase digestions and Mass Spectrometry revealed a complex mixture of neutral and monosialylated multiantennary N-glycans with variable number of alpha 1-3-Gal-Gal antennae terminals. The most abundant neutral N-glycan has a composition of HeX(7)HexNAC4dHexl, Negative ion ESI-MS/MS confirmed the presence of the 0-3-Gal-Gal motif on each arm of the fucosylated biantennary N-glycan. The most abundant monosialylated glycan was HeX6HexNAC4d Hex, Neu5Acl, with the sialic acid linked to the terminal fl1-4-Gal-G1cNAc. Sialic acid on the antenna capping position was predominantly of the N-acetyl form.