Abstract: Vulvar intraepithelial neoplasia (VIN) is an increasingly common problem, particularly among women in their 40s. The term VIN is used to denote high-grade squamous lesions and is subdivided into usual-type VIN (including warty, basaloid, and mixed VIN) and differentiated VIN. Usual-type VIN is commonly associated with carcinogenic genotypes of human papillomavirus (HPV) and other HPV persistence risk factors, such as cigarette smoking and immunocompromised status, whereas differentiated VIN usually is not associated with HPV and is more often associated with vulvar dermatologic conditions, such as lichen sclerosus. Biopsy is indicated for any pigmented vulvar lesion. Treatment is indicated for all cases of VIN. When occult invasion is not a concern, VIN can be treated with surgical therapy, laser ablation, or medical therapy. After resolution, women should be monitored at 6 and 12 months and annually thereafter.