Topical 5-fluorouracil (5-FU) has proven effective in epidermoid cancers of the head and neck. Its effectiveness has been correlated with the ability of the patient's immunologic system to recognize new antigens. In this study, 8 patients with carcinoma in situ of the vulva were evaluated and treated with topical 5-FU. Evaluation and followup has been completed and the literature reviewed. The overall treatment response rate was 75%. Followup to date has been 3-39 months. Thirty-five cases were reviewed from this series and the literature with a similar outcome.