Objective: The aim of this study was to investigate the influence on fertility and pregnancy outcome in cervical intraepithelial neoplasia (CIN) patients after a loop electrosurgical excision procedure (LEEP) or cold-knife conization (CKC). Methods: 269 patients with CIN-II-III who wanted to conceive were prospectively enrolled in this randomized clinical trial to receive either the LEEP or CKC procedure. Fertility, neonatal and maternal outcomes were observed and compared. Results: 244 evaluable patients were divided into two groups. There were 124 in the LEEP group and 120 in the CKC group. The preterm premature rupture of membranes (16 vs. 8%; p = 0.03), preterm delivery rate (11 vs. 5%; p = 0.04) and low birth weight infants rate (<2,500 g) (10 vs. 6%; p = 0.04) were higher in the CKC group than in the LEEP group, but there was no difference in mean birth weight, cesarean delivery, labor induction, or neonatal intensive care unit admission. There was no case of neonatal mortality. Conclusions: In a prospective evaluation the findings of this study demonstrate that LEEP is safer for future pregnancies when compared to CKC. LEEP should be an appropriate choice for patients with CIN who want to become pregnant later in life.