OBJECTIVES. Retrospective study to analyse objectively the effectiveness and anatomic and functional consequences for the cervix of conservative CO2 laser treatment for cervical intraepithelial neoplasia. PATIENTS AND METHODS. Analysis of therapeutic effectiveness and anatomic consequences of 1,114 treated patients followed at our colpolaparotomy surgery clinic for cervical dysplasia since 1987. Evaluation of function consequences by comparison with a group of patients who delivered after laser CO2 therapy for dysplasia (n = 56) and a group of control patients (n = 95) with a similar type of dysplasia after delivery and no treatment. The clinical course of the pregnancy and delivery were compared between the groups in search for risk of prematurity. RESULTS. Good preservation of cervical anatomy was achieved after a rigorous treatment protocol only applicable with CO2 laser. The preservation of the junctional zone facilitated diagnosis of recurrence. The risk of prematurity was low. Therapy was successful in 93.4% of the cases. CONCLUSION. The choice of conservative therapy is essential, not only when the patient desires a pregnancy but also in others since preserved anatomy facilitates diagnosis of recurrence. This findings implicate the need for an unagressive energy source and also accepting the early diagnosis and treatment.