Lower genital tract intraepithelial neoplasia was the predominant indication for CO2 laser surgery in 203 patients treated at Wayne State University. One hundred nineteen patients had cervical intraepithelial neoplasia (CIN) III and, in the 99 patients who were adequately followed, the failure rate following the first treatment was 9%. Secondary treatment with laser surgery, cryosurgery or, in one instance, hysterectomy, was effective in treating all persistent CIN. Success in treating vaginal intraepithelial neoplasia with laser surgery was most favorable in patients who had not had prior pelvic irradiation. Small (less than 1.5 cm) vulvar intraepithelial neoplasia III was successfully treated in seven patients. Recalcitrant condyloma acuminata responded well to laser surgery in 31 patients.