During 1977-1983, 787 consecutive referred cases of CIN were treated by vaporization of a dome-shaped defect, by excision of a cylindrical specimen, or a combination of procedures where 48% were CIN III. Vaporization was used for 72% of CIN I, 76% of CIN II, and 64% of CIN III cases. Less than 15% of vaporization and all excision cases were done in hospital under anesthesia; 11% had delayed bleeding requiring attention (admission was required in 2%); 100% of CIN I, 96% of CIN II, and 96% of CIN III cases were cured. Persistent disease was diagnosed at the first (96%) or second (4%) visit. Subsequent treatment included laser and less than 1% hysterectomy. Overall cure for laser surgery was 99.5%. Sixty-eight patients subsequently became pregnant; outcomes were normally distributed. Treatment success is related to adequate volume of tissue removed.