A cervical smear is a test aimed at detecting precancerous lesions and cancer at an early clinical stage. The introduction of a Pap smear as a screening test has reduced the number of newly diagnosed squamous cell carcinomas of the cervix by 42% in 20 years. At the same time, an increase in the incidence of adenocarcinomas originating from glandular, endocervical cells, has been observed. The Bethesda system, which documents the presence or absence of glandular cells of the cervix and defines their pathologies, is currently recommended for evaluation of cervical cytology. Most of the prevention programs recommend to screen every 2–3 years. We report a case of two women with cervical clear cell adenocarcinoma – a rare subtype (5–7%) of adenocarcinomas, diagnosed in stage FIGO IB2 that developed despite regular (every year) cytological screening. The last Pap smears were performed 12 and 13 months before the diagnosis and no abnormalities were found. The results were normal and no endocervical cells were found in the smear. The radical surgical treatment was implemented, followed by an adjuvant therapy. In post-surgical tissues, HPV-18 DNA was detected in both patients. During 24 and 19 months of follow-up, no recurrences were noticed.