Three sialoglycoprotein fractions having reactivities against influenza A and B viruses (IV-A and IV-B) and influenza virus-hemagglutinin (IV-HA), were obtained by gel filtration using a Sephacryl S-300 column and an Asahipak GS-710 HPLC column from water-soluble fraction prepared from human meconium (ME-WSF). Molecular weights of sialoglycoproteins in these fractions were estimated as 746 kDa (P-Fr. 1-3), 4470 kDa (P-Fr. 1-2) and a more than 10,000 kDa (P-Fr. 1-1), respectively. The other in P-Fr. 2, with molecular weight estimated as 92 kDa, revealed positive but weak reactivity against IV-HA; however, the fraction did not show positive reactivity against either IVs-A or -B. All these fractions contained sialoglycoproteins with a high content of carbohydrates (31.0-59.3%, w/w). From their carbohydrate compositions, it can be suspected that sialoglycoproteins having O-glycosidically linked carbohydrate chains were predominating in the three fractions. In conclusion, it is suggested that at least three sialoglycoproteins with influenza virus-receptor activity showing different chemical properties to each other exist in human meconium.