Sixty cases of vulvar intraepithelial neoplasia (VIN) were analyzed clinicopathologically (24 VIN I, 9 VIN II, 27 VIN III). The ages of the patients ranged from 21 to 83 years (mean, 53.7). Colposcopic examinations showed the presence of white areas in 29 cases, red areas in 9, acetowhite areas in 6 and other alterations in 13. One-third of the lesions were multifocal. Pruritus and burning were present in 65% of the cases. Fifty-one percent of the cases showed histologic changes suggestive of human papillomavirus (HPV) infection; the mean age of those patients was significantly lower than that of patients without HPV infection. In 15 cases of VIN, HPV DNA testing was performed with Southern blot hybridization; in three (20%) of those specimens HPV 16 episomal DNA was identified. Epithelial alterations surrounding the areas of VIN were found in 24 cases (40%)-23 squamous cellular hyperplasias and 1 lichen sclerosus. Different types of treatment were performed according to the different grades of VIN: medical therapy, diathermocoagulation, local excision, hemivulvectomy and total vulvectomy. Follow-up was possible in 52 cases, with a mean of 33 months (range, 3-98). Two cases of VIN I showed progression of disease over 12-24 months.