During the past 20 years, pathologists have more carefully examined and more precisely classified glandular lesions of the endocervix, largely reflecting increased concerns about the diagnosis and pathogenesis of adenocarcinoma of the cervix. This review of glandular lesions of the cervix focuses on the following six issues surrounding the histologic diagnosis of the more common types of adenocarcinoma of the endocervix and their mimics: (1) the classification and recognition of preinvasive glandular lesions, (2) the distinction of invasive from preinvasive adenocarcinoma, (3) the definition and significance of microinvasive adenocarcinoma, (4) the epidemiology and pathogenesis of adenocarcinoma, (5) the identification and behavior of the more common subtypes of invasive adenocarcinoma, and (6) the recognition of benign lesions that mimic adenocarcinoma It is the author's opinion that most in situ and invasive adenocarcinomas of the cervix can be recognized and distinguished from benign mimics. In contrast, glandular dysplasia and microinvasive adenocarcinoma of the cervix are currently ill-defined and irreproducible terms that should not be used for diagnostic purposes. Although only brief descriptions of the biologic behavior of the various lesions and their therapy are included in this review, certain variants of endocervical adenocarcinoma have distinctive behaviors and should be classified appropriately to provide prognostication and help to guide therapy.