Of 106 patients with carcinoma in situ (CIS) of the vulva, 102 have been followed from 1 to 15 years. The average age of the patient was 47 years; however, 40% were under the age of 41. Twenty-seven percent had associated cervical malignancy. Only 4 patients developed invasive cancer. Of these, 2 were postmenopausal and the 2 younger patients had been immunosuppressed because of systemic disease; thus the subsequent invasive cancer. The incidence of recurrence was essentially the same whether the patient was treated by vulvectomy or wide local excision. In view of the uncertainties about the invasive potential of CIS of the vulva in young patients and the absence of a proved need for an extensive procedure, it is suggested that this entity be treated only by local excision.