Thirty-six patients with vaginal intraepithelial neoplasia were treated with the carbon dioxide laser. More than half of the patients had grade 3 vaginal intraepithelial neoplasia (carcinoma in situ). The majority of patients were treated in a single session; six patients were treated twice, and two patients were treated three times. In 92% of the patients, the lesions were completely removed by the laser without significant side effects.