In 1947, Liver described adenoid squamous cell carcinoma under the title of "adenoacanthoma of sweat gland". This tumor is not rare, but reported cases in literatures were relatively few. The tumor were frequently found in the sun-exposed skin; such as face, ear, neck etc.. The cases involving non-sun-exposed area, such as oral and labial mucosa, nosopharynx and vulva etc., were also reported. Therefore, the relation between the pathogenesis of adenoid squamous cell carcinoma and sun damage has been still debated. Immunohistochemical studies have recently suggested that this tumor is squamous cell carcinoma undergoing acantholysis. The authors experienced a case of adenoid squamous cell carcinoma of the vulva in a seventy-one year old female patient. She had suffered from itching sensation on vulva for 10 years, and palpable mass on vulva for 1 month. On gross examination, a pale gray pigmentation and erosion, was noted at the right labia major, the minor extending left labia major and minor. On microscopic examination, nests of atypical epithelial cells extending into the cornium showed an adenoid architecture. These were composed of a peripheral layers of cuboidal cell in a lacy pattern. And the glandular spaces contained dyskeratotic acantholytic tumor cells in central portion. Therefore we diagnosed this case as adenoid squamous cell carcinoma of the vulva.