Perchloric acid-soluble fractions (PASFs 1-3) which were obtained from cyst fluids of two patients [(Nos. 1 (blood group B) and 2 (blood group A))] with ovarian mucinous cystadenoma and one patient (No. 3 (blood group A)) with ovarian dermoid cyst in benign, were identified as glycoproteins by their chemical composition analyses, respectively. Reactivities of PASFs1-3 against blood group anti-sera and lectins suggest that these PASFs did not contain MN blood group substances, Vgu glycoproteins and T-active glycoproteins. PASF 1 was separated into 11 fractions by Sephacryl S-500 gel filtration. From chemical composition, SDS-PAGE and serological property of the main fraction (Fr. 5), other one fraction (Fr. 7) and mild acid hydrolysates of these two fractions, it is possible to presume that PASF 1 consisted of a large number of AB-active and fucose-rich glycoproteins with high molecular weights and some of these glycoproteins bear either NeuNAcα2→6GalNAc (sialyl Tn) group or both sialyl Tn and sialylated T groups.