This report describes the case of the youngest Japanese person to be diagnosed with endocervical clearcell adenocarcinoma. In September 2005, a 17-year-old female adolescent visited a physician because of vaginal bleeding. A cervical tumor was discovered, and the patient was referred to our outpatient department. Vaginal examination showed a bleeding tumor approximately 1.5 cm in size protruding from the cervical os. The cytological finding of the uterine cervix was positive for malignancy, and the histological diagnosis by punch biopsy was clear-cell adenocarcinoma of the uterine cervix. A radical abdominal hysterectomy and pelvic lymphadenectomy were performed on October 30. Macroscopic findings showed a tumor, 1.5 cm in diameter, growing from the right side of the uterine cervix. The pathological diagnosis was clear-cell adenocarcinoma of the cervix (PT1b1NR0M0). The patient was discharged from our hospital without any adjuvant therapy. No signs of recurrence have been detected in the 2-year follow up.