Objective: The purpose of this study was to evaluate a conservative cold-knife section technique for treatment of cervical intraepithelial neoplasia (CIN). This procedure can be adapted to patient age, preservation of childbearing potential and extent of dysplasia. Design: Prospective study. Setting: Gynecological Oncology Department in French Public Hospital. Population: A total of 460 women treated for CIN between 1985 and 1999 were included. Methods: A conservative cold-knife cervical section followed by blanket suture reconstruction was used in all cases. Main outcome measures: Immediate operative results, recurrence and reproductive function were assessed. Results: The mean length of the cervical specimen was 11.4 mm (range, 4-22 mm). Mean specimen thickness was strongly correlated with age: 10.6 ± 4.1 mm in women < 40 years versus 12.1 in women >40 years; p < 0.001. Complete excision was achieved in 395 cases (85.8% ). Post-operative bleeding was observed in 5 cases (1.1% ). The mean duration of follow-up was 62 months (range, 12.3-156.5 months). Recurrences developed in 26 patients (6.6% ) including CIN 1 in 9 cases, CIN 2 in 9 and CIN 3 in 8. No patient developed carcinoma. The actuarial risk of recurrence was 2.4% (± S.D., 0.9) at 24 months and 7.8% (± S.D., 1.9) at 60 months. A total of 52 pregnancies were observed in 39 patients. No case of de novo infertility was reported post-operatively. Amenorrhea was noted in 1 patient (0.1% ) and dysmenorrhea in 1 patient (0.1% ). Conclusions: This conservative cold-knife section technique is effective for treatment of CIN with low morbidity and little adverse effect on childbearing potential. Exposure of the squamo columnar junction (SCJ) greatly facilitates follow-up. Objective: The purpose of this study was to evaluate a conservative cold-knife section technique for treatment of cervical intraepithelial neoplasia (CIN). This procedure can be adapted to patient age, preservation of childbearing potential and extent of dysplasia. Design: Prospective study. Methods: A conservative cold-knife cervical section followed by blanket suture reconstruction was used in all cases. Main outcome measures Results: Immediate operative results, recurrence and reproductive function were assessed. Results: The mean length of the cervical specimen was 11.4 mm (range, 4-22 mm). Mean specimen thickness was strongly correlated with age: 10.6 ± 4.1 mm in women <40 years versus 12.1 in women> 40 years; p <0.001 Complete excision was achieved in 395 cases (85.8%). Post-operative bleeding was observed in 5 cases (1.1%). The mean duration of follow-up was 62 months (range, 12.3-156.5 months). Recurrences developed in 26 patients (6.6%) including CIN 1 in 9 cases, CIN 2 in 9 and CIN 3 in 8. No patient developed carcinoma. actuarial risk of recurrence was 2.4% (± SD, 0.9) at 24 months and 7.8% (± SD, 1.9) at 60 months. A total of 52 pregnancies were observed in 39 patients. No case of de novo infertility was reported post- operatively. Amenorrhea was noted in 1 patient (0.1%) and dysmenorrhea in 1 patient (0.1%). Conclusions: This conservative cold-knife section technique is effective for treatment of CIN with low morbidity and little adverse effect on childbearing potential. the squamo columnar junction (SCJ) greatly facilitated follow-up.