The cytologic distinctions between artifactual atypia induced by endocervical brush collection, endocervical glandular repair, and endocervical glandular dysplasia or neoplasia are often difficult. This difficulty is amplified by the lack of accepted cytologic criteria for endocervical glandular dysplasia, and the fact that earlier studies defining the significant cytologic features of endocervical adenocarcinoma in situ and endocervical adenocarcinoma (endocervical neoplasia) utilized a swab for endocervical cell retrieval. With the almost universal adoption of the endocervical brush, it is important to redefine those cytologic characteristics that differentiate true endocervical glandular dysplasia or neoplasia from reactive or reparative processes and instrument artifact. From our data, it appears that the classically described cytologic discriminators between a negative smear and smears of endocervical dysplasia or neoplasia are basically unchanged with some minor modifications for endocervical brush-collected samples.