Epithelial mucin and immunohistochemical localization of carbohydrate antigens (CA125, CA19-9) in normal endocervical glands and adenocarcinoma of uterine cervix were examined histochemically. The materials were obtained from 33 surgical cases with adenocarcinoma and 9 control cases. Serial sections were examined by the following procedures: 1) Digestive PAS reaction, 2) High iron diamine-Alcian blue pH 2.5 staining, 3) Modification PAS and Thionin Schiff reaction to differentiate sialic acid, 4) Immuno-peroxidase method. Histologically, these adenocarcinomas were classified into four subtypes, endocervical, intestinal, endometrioid and serous adenocarcinoma. Endocervical adenocarcinomas were differentiated into the endocervical-intestinal group and serous-endometrioid group by mucin profiles and distribution of carbohydrate antigens. In endocervical and intestinal types, sialomucin was predominant, this mucin being characterized by O-acetylated sialic acid. Immunohistochemically, CA19-9, CA125 and CEA were localized in this group. The latter group of tumors were serous and endometrioid adenocarcinomas, characterized by surface coat type sulphomucin and non-acetylated sialic acid, but CA19-9 and CA125 were not detected in these cases. Adenoma malignum was classified in endocervical type adenocarcinoma.