Immunoreactivities of prostatic acid phosphatase (PACP) and prostate-specific antigen (PSA) were demonstrated in normal anal glands of males (11 of 25) and urethral glands of both sexes (six of six), by indirect immunoperoxidase staining. These prostatic antigens were colocalized in nonmucous epithelial cells. In the anal gland, PACP and PSA were distributed exclusively in acinus-forming, tall columnar cells, while columnar cells with brush borders, goblet cells, and transitional cells in the duct were negative. The anal glands from 20 females were devoid of such acinar structures and were negative for the antigens. Normal urinary bladder mucosa (n = 17) lacked immunoreactivity. A few endocrine-type cells, which showed PACP immunoreactivity but no PSA staining, were identified in normal rectal mucosa (n = 17) and were found rarely in the anal gland. The results of the present study suggest (1) that the development of acinar cells in the anal gland is an androgen-dependent phenomenon, and (2) that the ability to express PACP and PSA is a feature common to cloacogenic glandular epithelium.