Vaginal adenosis is defined by the presence of metaplastic cervical or endometrial epithelium within the vaginal wall, thought to be derived from persistent Müllerian (synonymous with paramesonephric) epithelium islets in postembryonic life. Spontaneous vaginal adenosis appears to be a fairly common (present in about 10% of adult women) but mostly insignificant coincidental finding. In women prenatally exposed to diethylstilboestrol (DES), vaginal adenosis may arise in up to 90% and is associated with a high risk of vaginal carcinoma. Since the withdrawal of DES from the market, vaginal adenosis has virtually disappeared from the medical literature. A case of vaginal adenosis is presented in a middle-aged woman who had not been prenatally exposed to DES. The lesions differed from the spontaneous type by their sudden appearance, their extent and their pronounced subjective symptoms. It is speculated that protracted oral contraceptive intake may have played a causative role.