The association of clear cell adenocarcinoma of the vagina and vaginal adenosis with prenatal exposure to diethylstilbestrol (DES) is well-documented in the United States. In Europe, however, DES was never used in the therapy of threatened abortion and, therefore, clear cell adenocarcinoma and vaginal adenosis remained rare diseases. We report on the clinical and pathological features of a case of clear cell adenocarcinoma of the upper vagina in a 17-year-old German girl, who had a history of hypoplasia of the left kidney with an ectopic termination of the ureter in the upper vagina, removed surgically 2 years before. No previous report of a similar coincidence of vaginal clear cell carcinoma and a congenital disorder of the genitourinary tract exists. Congenital anomaly of the ureter interfering with the development and the differentiation of the distal Müllerian tract and its epithelium might have provided a similar histological basis for carcinogenesis in our patient to that in those provided exposed to DES.