A total of 543 patients with cervical intraepithelial neoplasia were treated with the CO2 laser; 441 were seen for follow-up. The success rate was 76.4% after 1 treatment and 98% after 2 treatments. Many patients who returned with apparent minor abnormalities at the 1st follow-up visit had normal colposcopic results and Pap smears 6 mo. later. The complication rate was low; no significant problems were caused by pain or bleeding at the time of treatment. Postoperative hemorrhage requiring hospital admission occurred in 1% of patients. Laser treatment should be carried out only in departments with colposcopic expertise.