Endometrial in situ extension of cervical cancer is extremely uncommon. Previous reports only present the cases of squamous cell carcinoma or related category. This report presented adenosquamous carcinoma of the uterine cervix that showed a paradoxical extension of each component in a 72-year-old patient. Main tumor in the cervix was revealed to be adenosquamous carcinoma. The glandular component extended to the vagina, while the squamous component grew into the entire uterine cavity and replaced the glandular epithelium. We presented the first case of adenosquamous carcinoma of the uterine cervix with vaginal and endometrial extension. Furthermore, the endometrium was replaced with squamous component, while the vagina was invaded by glandular component. The observed paradoxical extension of the present case was extremely rare.