OBJECTIVE To determine the validity and reproducibility of various cytologic criteria as discriminators between different glandular lesions of the cervix. METHODS Seventy-three cervicovaginal smears with glandular lesions and a documented histologic and/ or clinical correlation were studied. The lesions included reactive changes, low grade glandular intraepithelial lesion (LGIL) (encompassing endocervical glandular dysplasia), high grade glandular intraepithelial lesion (HGIL) (encompassing adenocarcinoma in situ) and invasive adenocarcinoma (IA). Twenty-three cytologic criteria were used to evaluate the smears, and the results were scored and statistically analyzed. RESULTS Reactive lesions consistently showed well-defined cell borders, normal nuclear/cytoplasmic (N/C) ratio, minimal or absent nuclear overlapping, round to oval nuclei with fine chromatin and prominent nucleoli. HGIL (adenocarcinoma in situ) showed feathered edges, rosettes, cell strips, increased N/C ratio, elongated nuclei, marked nuclear overlapping and nuclei with hyperchromatic, coarse chromatin. IA shared features with HGIL but had a greater tendency to show a dirty background, single cells, mitotic figures, nuclear pleomorphism and large nucleoli. Logistic regression studies indicated that the presence of mitotic figures, a dirty background and single cells increases the odds ratio for predicting invasion. LGIL showed features similar to those of high grade lesions, but the changes were more subtle. These lesions were also less cellular and less likely to show cell strips, feathered edges and rosettes. Similar to HGIL and IA, LGIL showed nuclear overlapping, increased N/C ratio, oval to elongated nuclei and nuclear hyperchromasia. CONCLUSIONS There is overlap between the cytologic criteria for the various glandular lesions of the cervix. However, some of these criteria can consistently distinguish clinically significant lesions from reactive benign changes seen in the glandular epithelium.