Antigens A, B, H, Lea, and Leb were demonstrated in the tracheal glands of 15 Lewis-positive secretors and 15 nonsecretors by the indirect immunoperoxidase technique. The detection of group-specific ABH antigens in mucous epithelium and intraductal secretory fluid was dependent on the secretor character. Whereas determination of secretor character was sometimes unreliable with anti-A and anti-B, the findings obtained by additional labeling with UEA1 were consistently correct. The secretors showed minimal gland labeling with anti-Lea and intensive labeling with anti-Leb; the nonsecretors, intensive Lea labeling and weaker or absent Leb labeling. Consequently, the determination of secretor character by ABH labeling could be verified by the behavior of the Lewis antigens. Since both morphologic structures and epithelial antigens are highly resistant to putrefaction, ABO and secretor character can also be diagnosed in badly decomposed tracheal wall specimens.