Vaginal intraepithelial neoplasia (VaIN) represents a rare and asymptomatic pre-neoplastic lesion. Its natural history and potential evolution into invasive cancer are uncertain. VaIN can occur alone or as a synchronous or metachronous lesion with cervical and vulvar HPV-related intra epithelial or invasive neoplasia. Its association with cervical intraepithelial neoplasia is found in 65% of cases, with vulvar intraepithelial neoplasia in 10% of cases, while for others, the association with concomitant cervical or vulvar intraepithelial neoplasias is found in 30-80% of cases. VaIN is often asymptomatic and its diagnosis is suspected in cases of abnormal cytology, followed by colposcopy and colposcopically-guided biopsy of suspicious areas. In the past, high-grade VaIN and multifocal VaIN have been treated by radical surgery, such as total or partial upper vaginectomy associated with hysterectomy and radiotherapy. The need to maintain the integrity of reproductive capacity has determined the transition from radical therapies to conservative ones, according to the different patients' characteristics.