Mucin 1 (MUC1) is abundantly expressed by various organs, including human placenta and endometrium. Since glycan modifications of MUC1 are potentially relevant for physiological as well as pathological processes, this study was aimed at establishing an expression profile of two MUC1 glycoepitopes, CA 15-3 and CA 19-9, in trophoblast throughout pregnancy. Immunohistochemical analysis of normal placenta demonstrated that trophoblast cells express both mucin antigens throughout gestation with a distinct staining pattern. The staining of villous trophoblast was non-uniform for both antigens, and stronger for CA 15-3. Only a proportion of extravillous trophoblast of the cell column, in decidual stroma or lining blood vessels was also stained. Whether the studied MUC 1 glycoforms can be linked to trophoblast cells invasion remains to be established.