Seven cases of adenocarcinoma of the vagina occurring in young women 15 to 22 years of age are reported. Six sought medical advice because of abnormal bleeding, which was assumed to be due to anovulation. Hormonal therapy delayed the correct diagnosis, which was not made until vaginal examination was performed. Vaginal smears contained rare suspicious or malignant cells in 3 cases but were negative in 3 others, indicating that cytologic examination is unreliable as a diagnostic aid. Six of the tumors were clear-cell carcinomas, or so-called mesonephromas, and one was an endometrioid carcinoma. The frequent presence of vaginal adenosis and other evidence suggested that the clear-cell carcinomas were of müllerian and not mesonephric origin. Although the follow-up has not been long, radical surgery with vaginal replacement and ovarian conservation appears to have been a safe and effective method of therapy.