Ten monoclonal antibodies and one lectin were used to study the localization and distribution of Blood Group ABH, type 1 chain (Lewis a, Lewis b) and type 2 chain (H-2, Y) antigens in 22 cases of normal uterine cervix, with known ABO and Lewis phenotype and secretor status. The results showed that ABH isoantigen expression is clearly related to the secretor status. It is positive in the endo- and exocervical epithelium of secretor individuals and negative in non-secretors. Lewis antigen expression in both endocervical and exocervical epithelium is related to the patient's Lewis phenotype and is clearly controlled by the secretor gene. Indeed, the expression of the Lewis a antigen is limited to the tissue of people of Lewis (a + b-) phenotype (non-secretors), and the expression of Lewis b antigen is limited to the tissue of people of Lewis a-b+) phenotype (secretors). The Y antigen showed a focal expression in endocervical mucosa in all the cases, independently of secretor status or Lewis phenotype. The same pattern was observed for H-type 2 antigen, though only in secretor individuals.