OBJECTIVE: The aim of the study was to determine the impact of screening modality on the detection of cervical adenocarcinoma in situ (AIS) and adenocarcinoma. MATERIALS AND METHODS: This was a cross-sectional study of patients with AIS or adenocarcinoma who had undergone routine screening with cytology and high-risk human papillomavirus (HPV) cotesting between January 2007 and December 2017. Patients were stratified into 3 groups by screening test results: (1) HPV positive with abnormal cytology (HPV+/Pap+), (2) HPV negative with abnormal cytology (HPV-/Pap+), and (3) HPV positive with normal cytology (HPV+/Pap-). Demographic and clinical characteristics were collected. Data were analyzed with χ2, Fisher exact tests, and t tests as appropriate. RESULTS: Of the 118 patients diagnosed with AIS (n = 97) or adenocarcinoma (n = 21) after abnormal screening tests, 92 (78%) were detected by HPV+/Pap+, 15 (12.7%) were HPV+/Pap-, and 11 (9.3%) were HPV-/Pap+. Demographics were similar between groups, although the HPV+/Pap- patients had higher body mass indices. Rates of definitive hysterectomy were similar between groups (53.3%-80.0%, p = .11). CONCLUSIONS: In our cohort, a significant proportion of AIS and adenocarcinoma was detected by both HPV alone (with normal cytology) and cytology alone (with negative HPV), suggesting that cotesting with both HPV and cytology may be a more sensitive method of detection of AIS and adenocarcinoma.